
Class ^Fg .e^ 

Book. , H \S 



C^M W iQf^Z 



C.OFURIGHT DEI>OSm 



WORKS OF PROF. C. LARSEN 

PUBLISHED BY 

JOHN WILEY & SONS, Inc. 



Exercises In Farm Dairying. 

By C. Larsen, M.S.A. The Loose Leaf Labo- 
ratory Manual of The Wiley Technical Series, 
J. M. Jameson, Editor. An Elementary Man- 
ual for Agricultural High Schools and Colleges; 
a Practical Guide for Farmers and Dairymen. 
4to, paper, $1.00 net. 



By McKAY AND LARSEN 
Principles and Practice of Butter-maliing. 

A Treatise on the Chemical and Physical Prop- 
erties of Milk and its Components; the Hand- 
ling of Milk and Cream, and the Manufac- 
ture of Butter Therefrom. By G. L. McKay, 
Secretary, American Association of Creamery 
Butter Manufacturers, formerly Professor of 
Dairying in the Iowa State College, Ames, la., 
. and C. Larsen, M.S.A. Third Edition, Largely 
Rewritten, xiv + 40.5 pages, 6 by 9. 133 
figures. Cloth, $3.00 net. 

By LARSEN AND WHITE 
Dairy Technology. 

A Treatise on the City Milk Supply, Milk as a 
Food, Ice Cream Making, By-Products of the 
Creamery and Cheesery, Fermented Milks, 
Condensed and Evaporated Milks, Milk Pow- 
der, Renovated Butter, and Oleomargerine. By 
C. Larsen, M.S.A., and Wm.White, B.S. xiii-f- 
298 pages. 5iby8. 48 figures. Cloth, f2.00net. 



PRINCIPLES AND PRACTICE 

OF 

BUTTER-MAKING 



BY 

G. L. McKAY, Dr.Sc. 

Secretary, American Association of Creamery Butter Manufacturers, 
formerly Professor of Dairying in the Iowa State College, Ames, la. 

/> AND 

C. LARSEN, M.S.A. 

Professor of Dairy Husbandary, So. Dak., State College, Brookings, S. D. 
formerly Associate Professor, Iowa State College, Ames, la. 



THIRD EDITION, LARGELY REWRITTEN 

TOTAL ISSUE, SEVENTEEN THOUSAND 



NEW YORK 

JOHN WILEY & SONS, Inc. 

London: CHAPMAN & HALL, Limited 
1922 



rA\S 



Copyright, 1906, 1908, 1922, 

BY 

G. L. McKAY AND C. LARSEN 




PRESS OF 

BRAUNWORTH &. CO. 

BOOK MANUFACTURERS 

BROOKLYN, N. Y. 



MAY- 
©CI.A659863 



PREFACE TO THIRD EDITION 



The science of dairying is constantly broadening. The 
methods and art of manufacturing the best quality of butter 
have gradually changed in conformity with the scientific prin- 
ciples involved, and no one should now undertake to manufac- 
ture butter until he has made a careful study of the principles 
governing the best methods of manufacture. 

The authors admit that, in our present state of knowledge 
and experimental progress, it is in some instances difificult to 
distinguish well-established facts from those not universally 
confirmed; hence, it has been their object to give only informa- 
tion supported by the preponderance of experimental evidence. 

The first and second editions of this book have been received 
by the dairy schools and the practical creamerymen m a manner 
indicating that the work has met with general approval. The 
third edition has been carefully revised, and additional chapters 
have been added. The new chapters are : first. Defects Found in 
Butter — Some of the Causes and -their Prevention; second, 
Neutralization of Cream; third, Milk and its Products as Foods — 
High Value of Milk Fat; fourth. Cold Storage and Butter for 
Storage Purposes; fifth. New Tests, including Accurate Method 
of Determining Per Cent of Fat in Buttermilk, Skim-milk and 
Ice Cream. The authors' endeavor has been to bring the book 
strictly up to date, and to include the latest and most approved 
methods in dairying. 

The authors believe that the subject of dairying should no 
longer be treated as a whole, and for this reason have treated 
special branches of the subject. In this volume they have en- 
deavored to give such scientific information as relates to the 
manufacture of butter. 



IV PREFACE 

The scientific knowledge embodied in the present book has 
been acquired^ from time to time, through work done by various 
investigators at different Experiment Stations and by leading 
scientists of the Federal Dairy Division. 

It may be added that the statistics and tables given in this 
work have been quoted from noted, reliable authorities. 

The authors are indebted to the following companies and 
individuals for the use of electrotypes: Cherry Brothers, Cedar 
Rapids, Iowa; Waterloo Cream Separator Company and Iowa 
Separator Company, Waterloo, Iowa; Vermont Farm Machine 
Company, Bellows Falls, Vermont; Burrell & Company, Little 
Falls, New York; Empire Cream Separator Company and Jensen 
Creamery Machinery Company, Bloomfield, New Jersey; 
Dairy Queen Mfg. Company, Flora, Indiana; Elyria Enameled 
Products Company, Elyria, Ohio; Rice & Adams, Buffalo, 
New York; Worcester Salt Company, New York City; Russell 
& Hastings, Madison, Wisconsin; Louis F. Nafis, Creamery 
Package Company, Borden & Selleck Company, De Laval 
Separator Company, Arnold & Company, Diamond Crystal 
Salt Company and Davis-Watkins Dairymen's Mfg. Company, 
Chicago; Kirschbraun & Sons, Omaha, Nebraska; Professor 
M. Mortenson, Ames, Iowa; and Strawberry Point Creamery, 
Strawberry Point, Iowa. 

G. L. McKay. 

April, 1022. ^ ^ 

C. Larsen. 



CONTENTS 



CHAPTER I 

PAGE 

History of Butter-making and Composition of milk i 

1. Definition of Milk 3 

2. Composition of Milk 4' 

3. Variation of Total Solids 5 

4. Water 6 

5. Fat in Milk 8 

6. Properties of Fat 10 

7. Glycerides of Fat 10 

8. Condrcion of Fat n 

9. Theories in Regard to Films Enveloping Fat Globules 11 

10. Classes of Fats 13 

A. Volatile 13 

B. Non-volatile 14 

11. Composition of Butter Fat 15 

12. Proteids (Albuminoids) 16 

A . Casein 17 

B. Albumen 18 

13. Sugar . 18 

14. Ash 19 

15. Gases of Milk 20 

16. Coloring Matter 22 

17. Other Constituents of Milk 22 



CHAPTER H 

Milk Secretion 23 

1. Mammary Gland as a Secretory Organ 23 

2. Internal Structure of Cow's Udder 23 

3. Theories of Milk Secretion 26 

4. Conditions Affecting Secretion of Milk 28 

5. External Appearance of Udder . . 30 

6. Milk Fever 30 

V 



VI CONTENTS 

» 
CHAPTER III 

PAGE 

Properties of Milk 32 

1. Color 32 

2. Flavor 32 

3. Opacity of Milk 32 

4. Chemical Reaction of Milk 5^ 

5. Specific Gravity of Milk 33 

6. Natural Separation of Milk and Cream 35 

7. Adhesion of Milk 37 

8. Viscosity of Milk 37 

9. Specific Heat of Milk 38 

10. Effect of High Heating on Properties of Milk 38 

(i) Destroys nearly all Germs 39 

(2) Diminishes Viscosity or Body 39 

(3) Drives off Gases 40 

(4) Imparts a Cooked Taste 40 

(5) Precipitates Albuminoid and A?h Constituents 41 

(6) Destroys Properties of Enzymes 41 

(7) Divides the Clusters of Fat Globules 42 

(8) Caramelizes the Sugar 42 

General Remarks 42 

CHAPTER IV 

Milk and Its Products as Foods — High Value of Milk-fat 43 

1. Ciiemical Classification of Milk and Its Products as Foods 44 

2. Biological Classification of Foods 45 

A . Proteins 46 

B. Ash or Mineral Matter 46 

C. Two Unidentified but Essential Food Substances 47 

CHAPTER V 

Ferments in Milk 54 

1. Definition 54 

A. Classification of Enzymes 54 

2. Size and Shape of Bacteria 55 

3. Favorable Conditions for Bacterial Growth 55 

A. Food 55 

B. Temperature 56 

C. Moisture 58 

4. Unfavorable Conditions for Bacterial Growth 58 

5. Kinds of Germs Found in Milk 60 

6. Number of Bacteria in Milk 62 

7. Sources of Bacteria in Milk 62 

8. Effect of Thunder Storms on Souring Milk 64 



CONTENTS Vli 
CHAPTER VI 

PAGE 

Abnormal Milk 65 

1. Colostrum Milk 65 

2. Salty Milk 66 

3. Bloody or Red Milk 67 

4. Blue Milk 68 

5. Yellow Milk 68 

6. Ropy Milk 68 

7. Bitter Milk 69 

8. Milk from Cows which Have Been in Milk a Long Period 71 

9. Milk from Spayed Cows 72 

10. Milk from Sick Cows 72 

CHAPTER VII 

Variation of Fat in Milk and Cream 74 

PART I 

Variation of Fat in Milk 74 

1 . Individuality of Cows 74 

2. Breed of Cows 75 

3. Time between Milkings 75 

4. Manner of Milking , 76 

5. Fore and After Milk 77 

6. Age of Cow 78 

7. Advance in Lactation 78 

8. Feed of Cows 79 

9. Environment 80 

10. Condition of Cow 80 

PART II 

Variation of Fat in Cream 81 

1. Cream Screw Adjustment 82 

2. Richness of Milk 83 

3. Rate of Inflow 85 

4. Speed of Machine 87 

5. Temperature of Milk 88 

6. Amount of Water or Skim Milk Used to Flush the Bowl 90 

CHAPTER VIII 

Receiving, Sampling, Grading and Testing Milk and Cream 92 

I. Receiving and Grading of Milk and Cream 92 

A. Detection of Abnormal Milk and Cream through the Senses. . . 93 

B. Use of Acid Tests 94 



viil CONTENTS 

PAGE 

C. Use of Fermentation Tests 94 

a. Gerber and Wisconsin Curd Tests 95 

D. Grading Milk by Heating 96 

E. Use of Babcock Test and Lactometer 97 

a. Babcock Test of Milk 98 

b. Babcock Test of Cream 99 

c. Does the Babcock Test, as Ordinarily Applied to Cream, 

Give Too High a Reading? 100 

d. Babcock Test of Buttermilk and Skim-milk — American 

Association Test loi 

e. American Association Test 103 

/. Determination of the Per Cent of Fat in Butter 107 

F. Sediment Test 116 

2. Necessity of Good Milk 117 

3. Sampling of Milk ii8 

4. Sampling Tube 120 

5. Sampling Churned Milk 122 

6. Frozen Milk 1 23 

7. Sour and Coagulated Milk 123 

8. Apportioning Skim-milk 1 24 

9. Washing Cans 125 

CHAPTER IX 

Composite Samples 127 

1. Definition 127 

2. When to Sample 127 

3. Kind of Preservatives to Add 127 

4. Arrangement of Composite Samples 128 

5. Care of Composite Samples 129 

6. Average Sample 130 

7. Composite Sampling without the Use of Preservatives 130 

CHAPTER X 

Creamery Calculation 131 

1. Find Average Per cent of Fat 131 

2. Calculation of Overrun . . . 133 

(i) Thoroughness of Skimming 133 

(2) Completeness of Churning 133 

(3) General Losses in Creamery 133 

(4) Composition of Butter Manufactured 133 

3. Calculation of Churn Yield 135 

4. What Should the Overrun in a Creamery Be? 135 

5. Calculation of Dividends 137 

6. Cream Raising Coefficient 140 

7. Statement to Patrons 140 

8. Paying for Fat in Cream as Compared with Paying for Fat in Milk . . 143 



CONTENTS ix 



CHAPTER XI 

PAGE 

Heatesg Milk PEE\^ou5 to SKiMMrso 145 

1. Reasons for Heating 145 

2. Advantages of Warming Milk to High Temperature Previous to 

Skimming 146 

3. How Heated 147 



CH.\PTER Xn 

Sepae-^tiox op Cezam 149 

1. Gra\-it>' Creaming 149 

A. Shallow-pan System 149 

J5. Deep-setting System 150 

a. Probable Explanation 152 

C. Water-dUution Cream rHj-draulic) 153 

2. Centrifugal Creaming 154 

A . Advantages 155 

B. Histor>' of Centrifugal Separators 155 

C. Modem Separators 157 

D. Classification of Separators 158 

£. Process of Separation 158 

F. Conditions Affecting Efl5cienc>' of Separators 161 

a. Manner of Heating IMJlk 161 

h. Condition of the Milk 163 

c. CKerfeeding the Separator 163 

d. Speed 164 

e. Steadiness in Running 165 

/. Thickness of Cream 165 

g. Slush in Bowl 165 

h. General Remarks 166 



CH.\PTER Xin 

Earm Separ.\tors 168 

1. Introduction of Farm Separators 168 

2. Reasons for Introducing Farm Separators 168 

3. Objections to Farm Separators 171 

4. Thickness of Cream 172 

5. Po%ver for Farm Separators 1 74 

6. Care of Cream on the Farm 176 

7. Disposition of Cream 179 

A . Shipping of Cream 180 

B. Making Butter on the Farm 180 



CONTENTS 



CHAPTER XIV 

PAGE 

Neutralization — The "Neutralization" of Cream. . ' 183 

1. Neutralization, Principle of 183 

2. Neutralization of Cream for Butter-making 184 

3. The Preparation and Use of Lime as a Neutralizer 192 

4. Pints of Lime Mixture Required to Reduce Acidity to .25 Per Cent 

(Table) 196 

5. Other Neutralizers 199 



CHAPTER XV 

Pasteurization 201 

1 . Definition 201 

2. Storch Test for Pasteurization 201 

3. Pasteurization Temperatures 202 

4. Good Milk and Cream Important 204 

5. Sanitation Must Accompany Pasteurization 206 

6. Methods of Pasteurization 208 

A . Flash or Instantaneous Method 208 

B. Vat or Holding Method 208 

C. Combined Flash and Holding Method 208 

7. Efficiency of Pasteurizers 210 

8. Cost of Pasteurization 212 

9. Disadvantages of Pasteurization 214 

10. Advantages of Pasteurization ,. 214 



CHAPTER XVI 

Cream Ripening and Starters 215 

Cream Ripening: 

1. Definition ^ . 215 

2. Objects of Ripening 215 

3. Ripening Temperature of Cream 220 

4. Amount of Starter to Add to Cream 221 

5. Mixing the Starter with the Cream 221 

6. Tests for Acidity 221 

A . Mann's Test 222 

B. Farrington Test 223 

7. Degree of Acidity that Cream Should be Ripened to 224 

Starters: 

8. Definition 225 

9. History 226 

10. Classification of Starters 226 

11. Preparation of Natural Starters 226 



CONTENTS xi 

PAGE 

12. Commercial Starters or Cultures 227 

13. Preparation of Commercial Starters 230 

14. Inoculation 232 

15. Milk Powder for Starters 235 

16. Length of Time a Starter Can be Carried 236 

17. Poor Starters 236 

18. Under-ripening and Over-ripening of Starters 237 

19. Amount of Starter to Use 237 

20. Use of Starter-cans 238 



CHAPTER XVII 

Churning and Washing Butter 239 

1. Definition 239 

2. Conditions Affecting the Churnability of Cream 240 

A . Temperature 240 

B. Influence of Length of Time Held at Churning Temperature. . . 245 

C. Richness of Cream 245 

D. Amount of Cream in Churn 247 

E. Degree of Ripeness 248 

F. Nature of Agitation 249 

G. Size of Fat Globules 252 

3. Straining of Cream 253 

4. Color 253 

5. When to Stop the Churning 255 

6. Churning Mixed Sweet and Sour Cream 258 

7. Difficult Churning 258 

8. Keeping Churn in Sweet Condition 260 

9. To Prevent Butter from "Sticking" to Churn 262 

10. Washing of Butter 263 

A . Purpose of Washing 263 

B. Temperature of Wash Water 263 

C. Kind of Wash Water to Use 265 

11. Methods of Purifying Wash Water 266 

A. Filtration 266 

a. Continuous 269 

b. Intermittent 270 

B. Pasteurization . 266 

12. Advantages of Purification of Wash Water 271 



CHAPTER XVIII 

Salting and Working of Butter , . 272 

1. Objects of Salting , . . . 272 

2. Amount of Salt to Use to Produce Proper Flavor 272 

3. Effects of Salt upon Keeping Properties. , , . 272, 273 



XU CONTENTS 

PAGE 

4. Salt Facilitates the Removal of Buttermilk 275 

5. Salt in Relation to Water in Butter 275 

6. Kind and Condition of Salt 277 

7. Gritty Butter 278 

8. Mottled Butter 279 

g. Prevention of Mottles in Butter 284 

10. Curdy Specks in Butter 285 

11. Brine Salting 287 

12. Salt Test 288 

A . Principles of the Test 288 

B. Chemical Changes that Take Place 288 

C. Features of Practical Salt Tests 289 

D. To Make a Salt Test 290 

13. Working of Butter, Objects of 291 

14. Moisture Tests of Butter 293 



CHAPTER XIX 

Preparing Butter for Market and Prevention of Mold 294 

1. Styles of Package and Kinds of Wood Used 294 

2. Storing Butter in Creameries 296 

3. Cost of Manufacturing Butter 297 

4. Treatment of Tubs and Boxes 300 

5. Paraffining of Tubs 302 

6. Paraffining Tubs Reduces Loss from Shrinkage 303 

7. Treatment of Parchment Paper 304 

8. Yeasts and Molds in Butter 304 

9. Mold on Butter 306 

A . Conditions Favorable to Growth of Molds 307 

B. Discolorations 307 

C. Propagation of Molds 307 

D. Sources of Mold on Butter 307 



CHAPTER XX 

The Composition of Butter and Factors that Influence its Control. . . 309 

I- Acts and Rulings as to Composition of Butter 309 

2. Compounds for Increasing Yield of Butter 310 

3. Need for Regulations 311 

4. Control of Moisture in Butter 312 

5. Analyses of Commercial Butter between Thirty and Forty Years Ago. 315 

6. Standards in Different Countries 317 

7. Factors that Aid in Moisture Control 318 



CONTENTS Xlll 

CHAPTER XXI 

PAGE 

Defects Found in Butter — Some of the Causes and Their Prevention 323 

1. Flat or Insipid Flavor 3 23 

2. Stable Flavors 3 24 

3. Flavors Acquired by Absorption 324 

4. Cheesy Flavor 324 

5. Sour Flavor 325 

6. Faulty Factory Conditions 325 

7. Feed Flavors 327 

8. Removal of Garlic or Onion Flavors 327 

A. To Eradicate Wild Garlic 328 

9. Advance in Lactation, Winter Feeds and Stable Conditions 3 29 

10. Tallowy Flavor 332 

11. Metallic Flavors , 335 

1 2. Fishy Flavor 336 



CHAPTER XXII 

Judging and Grading Butter 340 

1. Standard for Judging 340 

2. Manner of Judging 341 

A . Body 341 

B. Flavor 341 

C. Color 341 

D. Salt 342 

E. Style 342 

3. Classification — Grades and Scores 342 

A . New York Classif cation 342 

B. Chicago Classification 347 

4. Export Butter 350 



CHAPTER XXIII 

Cold Storage and Butter for Storage Purposes 352 

1. History of Cold Storage. 352 

2. Mechanical Refrigeration 353, 363, 375 

3. Benefits of Cold Storage 353 

4. Cost of Storage 355 

5. Should Cold Storage Butter be Branded? 356 

6. Butter for Storage 357 

7. Working and Packing Butter for Storage Purposes 360 



XIV CONTENTS 

CHAPTER XXIV 

PAGL 

Cooling Facilities for Creameries 362 

I. Cooling Systems — Natural Ice, Mechanical Refrigeration and Cold 

Water 362 

A. Natural Ice System 365 

a. Kind of Ice House 365 

b. Size and Shape of Ice House 368 

c. Filling the Ice House 372 

d. Source of Ice 373 

B. Use of Ice in Cooling Cream 374 

a. Directly 374 

b. Indirectly 374 

C. Mechanical Refrigeration 375 

a. Application in Creameries : . '. 375 

b. Chemicals Used for Mechanical Refrigeration 376 

c. Principles of Producing Cold Artific ially 376 

(i) Compression 377 

(2) Condensation 377 

(3) Expansion 378 

d. Transferring the Cold. ....'. 378 



CHAPTER XXV 

Economic Operation of Creamery 381 

1. Firing the Boiler 381 

2. Burning Wood or Coal 382 

3. Daily Weighing of Coal Used 383 

4. Cleaning the Boiler 384 

5. Priming of Boilers 384 

6. The Injector 385 

7. Oil Separators 385 

8. Belt, Pulley and Speed Calculation 385 



APPENDIX 

I. Legal Standards for Dairy Products 387 

II. Metric System of Weights and Measures 388 



BUTTER-MAKING 



CHAPTER I 

HISTORY OF BUTTER-MAKING AND COMPOSITION 

OF MILK 

The art of butter-making in some form dates back to time 
immemorial. History tells us that butter is one of the oldest, 
as well as one of the most universal, articles of diet. We are told 
it was used in some form two thousand years before the birth of 
Christ. References are made to it in early Biblical and other 
ancient history. We read, in Genesis, that when Abraham was 
visited by Angels, who appeared in the form of men, " he took 
butter and milk and the calf which he had dressed and set it 
before them." The word " butter " is mentioned in the Bible 
seven times. It is known that the Scythians and Greeks used 
butter in 450 B.C. A little later there is a record of the Persians 
making and using it. In the early centuries butter was employed 
in many ways. The Hindoos offered it as a sacrifice in their 
worship. The Greeks and Romans did not eat it, but used it 
as a remedy for injuries to the skin. It was considered by them 
that the soot of burned butter was good for sore eyes. The 
Romans also used it as an ointment for the skin and the hair. 
This practice was common in Macedonia, and it is reported that 
in many cold regions persons use butter as a bath. In Spain, as 
late as the seventeenth century, it was found in medicine shops for 
external application only. In the rural districts in Germany, 
fresh unsalted butter has been employed as a cooKng salve for 
burns, and has been used to some extent in this country. 

In early times, butter was not generally used as a food, but 



2 BUTTER-MAKING AND COMPOSITION OF MILK 

when It was this was for the purpose of enriching other foods in 
cooking. We are told it was stored in a melted condition, and 
was never eaten when fresh. 

In the early methods of making butter, churning was brought 
about by agitation of whole milk. In our own country at the 
present time, in some of the Southern States, the method of churn- 
ing whole milk rather than cream is still followed by farmers' 
wives. Some difference of opinion exists as to the early methods 
used for creating agitation sufficiently to gather butter from the 
milk. Such methods were used as placing the milk in earthen 
vessels and beating it with the hands until butter formed. 
Later, wooden stirring sticks were used for the purpose of creating 
agitation. The Arabs churned their milk by placing it in leather 
bags and dragging them over the ground by means of a rope 
attached to a horse's saddle. Another method used was that of 
placing the milk in skin bags, fastening them to a tree and 
swinging them back and forth to bring about agitation. (See 
cut. Chapter XVII.) As time passed, more complete devices 
or methods were adopted for churning, such as the dash churn. 
Following the dash churn came the square box churn — which was 
used extensively in creameries about twenty years ago — and the 
table butter worker. Now we have the modern up-to-date 
combined churn. Setting milk in cold water and permitting 
the cream to rise lessened the time of churning and brought the 
manufacture of butter down to a science. 

The adoption of the centrifugal machine for separating 
the fat from the milk was one of the greatest advancements in 
butter-making. (See cut of first centrifugal machine in Chap- 
ter XII.) The first centrifugal cream separator used in Iowa — 
possibly the first used in America — was a power separator which 
Jeppe Shpsgaard brought with him from Denmark in 1882, and 
which was used in a Danish community near Cedar Falls, in 
Black Hawk County. It is worthy of note that this machine 
was so novel to the customs officers in New York that they held it 
for two months before they could decide as to whether it was 
constructed of iron or steel. They finally decided that it was of 
steel construction and fixed the duty at S93. 



DEFINITION 3 

Marked improvements have been made in the manufacture 
of butter by the adoption of scientific methods and the use of 
modern equipments. Changes have been made in the period of 
lactation. Formerly the cow furnished milk only for her young. 
Through the efforts of man, by breeding and selecting, the period 
of lactation has been lengthened until at the present time it 
extends over a period of ten months. The cow at the present 
time is recognized as one of the most economical producers of 
human food, hence, dairying has advanced rapidly in all coun- 
tries that are adapted for the production of forage plants that are 
suitable for feeding the cow. 

The United States at the present time produces five times as 
much butter as any other country. The late census estimates 
863,577,000 pounds of factory butter manufactured in 1920 and 
675,000,000 pounds of farm butter. 

Notwithstanding the number of years that butter, milk and 
other dairy products have been used for food, it is less than ten 
years since the physiologists discovered that butter and milk 
contained certain food elements that are essential for the growth 
of the young that had escaped investigations made by eminent 
chemists. This discovery was brought about by feeding experi- 
ments by such noted physiologists as Dr. F. G. Hopkins of Cam- 
bridge University, England, and Dr. E. V. McCoUum of Johns 
Hopkins University in this country. The discoveries made by 
these eminent authorities will no doubt be the means of creating a 
greater demand for dairy products of all kinds. 

Definition. — Normal milk is a liquid secreted in special glands 
of all females belonging to the mammalian group. It is composed 
chiefly of water, proteids, fats, sugar, and minerals. Coloring- 
matters and gases and some organic acids are found in small 
quantities. 

All normal milk from the different classes of animals, such as 
mare, buffalo, goat, ewe, ass, and cow, has a general resemblance 
in that it all contains water, fat, proteids, sugar, and ash. But 
milk from different animals varies in the relative proportions of 
its constituents. The chemical and physical properties are not 
alike. When human milk is treated with half its volume of 



4 BUTTER-MAKING AND COMPOSITION OF MILK 

ammonium hydrate and kept at a temperature of 60° C. for 
about twenty minutes, it assumes an intense red color. Cow's 
milk turns faintly yellow if treated in the same way. This test 
was reported by Unikoff, of St. Petersburg (now Petrograd), at 
the meeting of the Medical Section, Royal Academy of Med- 
icine, in Ireland. The various kinds of milk also differ from 
each other in their behavior towards rennet. Richmond has 
divided milk into two classes: Class I includes milk from tne 
ewe, buffalo, goat, and cow. When rennet is added to the 
milk from these animals, the casein coagulates into a firm curd. 
Class II includes human milk, milk of the ass, and mare. 
When rennet is added to the milk of these animals, a soft curd 
or none at all is formed. The latter class seems to include the 
animals without horns, while the first includes those with horns. 

As the cow's milk is used as a food to a greater extent than 
that of any other animal, it has been subjected to more extended 
and more careful investigation, and, as a consequence, more 
definite knowledge has been obtained concerning its composition, 
properties, and uses. The succeeding discussions have reference 
to cow's milk, if not otherwise stated. 

Composition of Milk. — It is impossible to get accurate figures 
on the composition of milk, as each of the milk constituents is 
subject to fluctuation from various conditions, such as individ- 
uality of cow, breed, season of the year, stage of lactation, milking 
and enviroimient. 

The average composition, as determined by 280,000 analyses 
reported by Richmond is as follows : 

Water 87.35 

Fat 3.75 

Milk-sugar 4 . 70 

Proteidsi C^^^^^ 3-00 



Albumen, etc . 45 

Ash 75 

The composition of various kinds of milk is given by Konig as 
follows : 



VARIATION OF TOTAL SOLIDS 



Human 

Mare ........ 

Buffalo 

Ass 

Cow 

Ewe 

Goat 

Sow 

Bitch 

Elephant 

Hippopotamus 

Camel 

Llama 



No. of 
Analy- 



107 

50 

8 

7 

793 

32 

38 

8 

28 

3 

I 

3 
3 



Water 



41 


3- 


78 


I. 


25 


7- 


64 


I 


17 


3 


82 


6 


71 


4 


04 


4 


44 


9 


30 


9 


•43 


4 


57 


3 


■55 


3 



Fat 



■51 
.64 
.69 
,86 
.78 
•55 
■57 

. ID 

•51 
.07 

■15 



Casein 
and Al- 
bumen 



4 
3 90 



Milk- 
sugar 



Ash 



Specific 
Gravity 



I .0270 

1^0347 
I ■ 0350 

I ■ 0345 
I .0316 
I. 0341 
I .0328 
1.038 

i^o35 
I ■ 0313 

1 .042 
1^034 



Variation of Total Solids. — As applied to milk, " Total 
Solids," is a term that includes fat, casein, albumen, sugar, 
and ash; in other words, all the milk constituents except the 
water. " Solids Not Fat " is a term often used, and includes 
the casein, albumen, sugar, and ash, or all the milk constituents 
except water and fat. " Serum " is a term used to designate all 
the milk constituents except the fat. The fat is the most val- 
uable constituent of the total soHds. The variation in the total 
solids of milk during the summer months is shown in the table 
quoted below from Dr. Van Slyke of Geneva, New York: 



Month 



May 

June 

July 

August. . . 
September. 
October. . . 



Per Cent 
of Water 



87.44 

87.31 

87.52 

87-37 

87 

86.55 



Per Cent of 


Total Solids 


12 


56 


12 


69 


12 


48 


12 


63 


13 




13 


45 



Dr. Van Slyke also studied the effect of the lactation period 
upon the total solids in milk. A herd of fifty cows, calving in 



6 



BUTTER-MAKING AND COMPOSITION OF MILK 



different months of the year, was used in the experiment. The 
per cent of total solids of this herd seems to average a little high 
all through the ten months. The total solids were found to be 
14 per cent during the first month, decreasing to 13.47 per cent 
during the next two months, then gradually increasing with the 
advance of the lactation period. In the tenth month the average 
total solids was 14.83 per cent. Pingree, of Pennsylvania, reports 
having found normal milk from a cow which contained 17.01 
per cent total solids. Sherman ^ reports a very high average 
total of the milk sohds. He treated the milk from thirteen cows, 
and found it to contain on an average 18.03 per cent of total 
solids. Konig reports a minimum of total solids of 9.31 per cent, 
a maximum of 19.68 per cent, and an average of 12.83 P^r cent. 
The average total solids quoted above from Richmond is 12.65 
per cent, which agrees closely with Konig 's results. 

The difference in total sohds of milk from some of the leading 
breeds has also been studied by Dr. Van Slyke, and the results 
are as follows : 



Breed 



Holstein. . 
Ayrshire. . 
Shorthorn 
Devon . . . . 
Guernsey. 
Jersey. . . . 



Per Cent 
of Water 



Per Cent of 
Total Solids 



12.75 
14 • 30 
14-50 
14.90 
15-40 



The maximum and minimum amounts of total solids men- 
tioned above are abnormal cases. The normal variations of 
the solids in milk are within comparatively narrow limits. For 
this reason the minimum standard for total milk sohds, in Slates 
where dairy laws are in force, is fixed by law. Usually 12 per 
cent is the minimum. 

Water. — From what has been said above concerning the total 
milk solids, it will be seen that water constitutes by far the largest 

^ Jour. Am. Chem. Soc. 



WATER 7 

portion of milk. It is quite uniform, and in milk from a mixed 
herd the water seldom falls below 86 per cent and seldom exceeds 
88 per cent. Variations ranging from a little less than 8o per cent 
to a trifle over 90 per cent are on record. But such variations 
must be looked upon as occurring in only a very few special cases. 

It has often been asserted that cows in the spring of the year, 
when they are pasturing on new grass, or feeding on other suc- 
culent foods, yield milk which contains an excess of water. Under 
such conditions there is a tendency for cows to produce milk with 
a water content a trifle higher, as has already been shown by the 
figures quoted from Dr. Van Slyke. As a rule this is much over- 
estimated. It is even a common occurrence to hear creamery 
operators say that their " soft " or " slushy " butter, in the early 
spring, is due to the excess of water present in the milk. This 
particular phase will be discussed further under the heading of 
" Fat in Milk." 

The following question has often been raised : Is the water in 
milk the same, or any more valuable than water obtained from 
other natural sources? The water in milk, so far as known, is 
transuded from the blood-vessels in the udder into the milk 
glands. It is so perfectly mixed with the other milk constituents, 
and holds the milk soKds in such perfect emulsion and solution 
that it would seemingly be impossible to prepare milk so per- 
fectly by artificial means. However, a substance is prepared by 
Jacob C. Van Marken, Neuweid, Germany, which, when added 
to water, produces a substance similar in appearance to watered 
skimmed milk. The preparation is named " Kalberrahm Vita." 
The first name literally means calf-cream. It has a syrupy 
consistency, and in appearance resembles light-brownish molasses. 
It is sold in tin cans, and recommended highly for calf feeding 
when mixed with skimmed milk. When mixed with water, it is 
recommended highly for hog-feeding. 

Water distilled from milk has the same appearance as ordi- 
nary distilled water. It is clear and colorless. The chemical 
reaction when phenolphthalein is used as an indicator is neutral, 
as is that of ordinary distilled water, even when distilled from 
milk in which acid has developed. But there is a considerable 



8 BUTTER-MAKING AND COMPOSITION OF MILK 

difference in the taste and smell. This indicates that some of 
the volatile substances are distilled over with the water. The 
probability is that these flavoring substances are so closely asso- 
ciated with water in milk that they are inseparable, and that the 
only place where this water can be prepared so as to assume these 
qualities is in the cow's udder. The conclusion would then be 
that the water in normal cow's milk cannot be distilled and 
replaced by natural water without the loss of the normal good 
flavor of the product. 

FAT IN MILK 

This is by far the most important constituent of milk, espe- 
cially to creamery operators. It exists in the milk in suspension, 
in the form of globules so small as to be invisible to the naked eye. 
Fat globules, at ordinary living-room temperature, are present in 
milk in a liquid form. Cooling the milk to a very low tempera- 
ture (about 50° F.) hardens them. When the globules are caused 
to unite, as in churning, they also solidify. 

The size of the fat-globules is very minute, and varies con- 
siderably, according to breeds, individual cows, and the stage 
in the lactation period. The globules in the milk from the same 
cow also vary a great deal. Lloyd found fat-globules in Jersey 
milk to be from 8 to 12 micro-millimeters in diameter. Very few 
were less than 4 micro-millimeters (a micro-millimeter is 10^00 
milKmeter, or 25000 of an inch) . The majority of the fat-globules 
in milk from Shorthorn cows measured from 6 to 8 micro- 
millimeters in diameter. According to Fleischmann, the size of 
fat-globules varies between 1.6 micro-millimeters and 10 micro- 
millimeters in diameter. A Danish investigator maintains that 
the diameter of fat-globules is between .0063 and .00014 rnilli- 
meter, and that i cubic centimeter of milk contains from 2.6 to 
1 1.7 milHon globules. He also asserts that a reflection of the 
light renders it very difficult to get the proper size of the fat- 
globules, as the light tends to make the globules appear larger 
than they are in reality. 

It has been maintained by some that the larger fat-globules 
contain fats which are different from those contained in the 



FAT IN MILK 



smaller globules. But this is by some investigators considered 
to be a matter of conjecture. Most authorities now believe 









a. 


Skim milk 








<- o " 


o 


o 


^ o 


°.° 


' , 


■^ 




o 




o 




« 


« 




o 


• e 
o 


• 




<^'o ' 


OO 


o 


o 


O 


• 


"o " 


0,° 




o 




6 


• 


o 







o 

o 


O " 




o 


« 








• 




r ' 






« 


. p,._ 


o 


•o 

o 





0,0 

Voo 


o 
'o 


•o 



6. Milk. 




QP^^o 0/2g^0 °«00^=^ ° O°o^^ 



^8Q>%°^go'goQ.^^6Vo^^s!) 







c?. Colostrum. 



Pe»e, 



Co 



. .<'q o 












Fig. I. — Microscopical appearance of different kinds of milk. Magnified 300 
times. (U. S. Farmers' Bui. No. 42.) 

that there is no difference in the kinds of fat of the different-sized 

globules, even though some experiments ^ show that fat composed 

1 Gembloux, Belgium, Creamery Jour., London, No. 8, Vol. I. 



10 BUTTER-MAKING AND COMPOSITION OF MILK 

of larger globules has a finer flavor, and a little more oily appear- 
ance. 

From what has been said, it will be seen that the minute- 
ness of the fat-globules is almost inconceivable. They were 
first discovered in 1697 by A. von Leeuwenhoek. The minute 
state of division, or the form of emulsion in which they exist 
in milk, renders it easy to digest when consumed as a food. 

Properties of Fat. — The specific gravity of pure butter-fat 
at 15° C. is .93002. The refractive index of butter-fat at 22° C. is 
on an average 1.459. The melting-point of pure butter-fat, as 
now determined, varies between 32° and 37° C. (90° F. and 
99° F.) 

When pure butter-fat is rapidly cooled, it sohdifies into one 
solid mass; but if allowed to cool gradually, part of it solidifies, 
and part of it remains a liquid longer than other parts. This 
seems to indicate that some fats with a high melting-point sepa- 
rate out from the fats with a low melting-point. This behavior 
of pure butter-fat is not well understood, as it contradicts the 
now accepted theory that the different fats are in chemical com- 
bination with each other, rather than a mechanical mixture of 
different glycerides of fat. 

Glycerides of Fat, — By this term* we understand that the 
fatty acid radicals are in chemical combination with the glycerol 
(glycerine) radical, thus: 

Fatty acid radicals. 



Glycerol radical. 
C3H5 



C4H7O2 (Butyric) 
C18H33O2 (Oleic) 
C18H35O2 (Stearic) 

The chemical formula for glycerine is : 



Glycerol radical. 
C3H5 



Hydroxyl groups. 

^ OH 

OH 
OH 



The difference and similarity of these two formulas are 
easily observed, and the reason why the term " Glyceride of Fat " 
has been applied to such a compound is evident. 



Butyrin . 




Olein. 


Stearin. 


' C4H7O2 




C]8H3302 


C18H35O2 




C4H7O2 


C3H5 


C18H33O2 C3H5 


Ci8H3502,etC. 




C4H7O2 




C]8H3302 


C18H3502 



CONDITION OF FAT 11 

Condition of Fat. — Whether the fats in milk exist in chemical 
combination, or whether they exist as glyceride of butyrin, 
stearin, olein, etc., in the form of a mechanical mixture, is a 
question in dispute. If they exist in the latter form, the composi- 
tion of the different fats must be as follows : 



C3Ht 



and the total fat made up of a mechanical mixture of these and 
the remainder of the fats in butter-fat. 

Richmond and other authors beheve that fat probably exists 
in milk chemically, as first mentioned and illustrated; because, 
if the fat were a mixture of glycerine tributyrate with other 
glycerides of fat, butyrin or glycerol tributyrate could be dis- 
solved out by the use of alcohol. But this is not the case. More- 
over, if butyrin existed separately in milk, it would be possible 
to distill it off under reduced pressure. This cannot be done. 

Theory in Regard to Films Enveloping Fat-globules. — The 
extreme minuteness of the fat-globules in milk renders it almost 
impossible to determine by direct microscopical observation 
whether there is a membrane around each globule or not. Fleisch- 
mann and Lloyd assert that, so far as they were able to detect, 
there is no real membrane surrounding each globule. 

The theory generally accepted in the past was that the film 
surrounding the fat-globules was simply due to surface tension, 
or to the fact that the molecules of the fat have a greater attrac- 
tion for themselves than they have for the molecules of the serum 
in which they are held in suspension. In support of this two 
arguments are advanced. 

(i) The natural milk-fat may be removed from milk and 
artificial fat substituted in its place. The resultant milk has 
characteristics similar to milk containing normal fat, that is, the 
emulsion which milk forms with the artificial fat is apparently 
like that formed with the natural fat. 

(2) If there were a special albuminous membrane around 



12 BUTTER-MAKING AND COMPOSITION OF MILK 

each fat-globule, cream should contain a higher percentage of 
albuminoids than milk. This, Richmond maintains, is not so. 

Dr. Storch concludes from extensive researches that there is a 
gelatinous membrane enveloping the fat-globules. His conclu- 
sions are based mainly upon the first three reasons given below. 
The other facts mentioned also support his conclusions : 

(i) When milk has been stained with ammoniacal picro- 
carmine, and the cream washed with water until it is free from 
milk-sugar, a stained layer is present around each globule. 

(2) He has succeeded in isolating this gelatinous substance 
from cream and butter. Owing to its existence in these two 
substances, he assumes that it is also present in milk. 

(3) When ether is added to milk, the fat-globules dissolve 
with difficulty, unless some alkali is added to the milk first. 

(4) Bichamp maintains that when ether is added to milk 
the fat-globules are enlarged due to the ether passing through the 
supposed membrane by the process of osmosis. He considers 
this fact sufficient to prove that there is a membrane encircling 
each globule. 

(5) Butter containing 85 to 86 per cent fat is asserted by 
Richmond to have the same consistency as cream containing 
about 72 per cent fat at the same temperature. The soHdity of 
butter is due to the close proximity of the fat-globules. Now, if 
cream with less fat has the same consistency as butter, the prox- 
imity of the fat-globules must be equal to that of the butter; 
this would indicate that there is a membrane and that this mem- 
brane increases the size of the fat-globules. 

(6) The fact that cream separated by centrifugal force is 
more easily churned than cream of the same richness separated 
by gravity methods, would also be explained if the fat-globules in 
milk had such a membrane surrounding them. 

This membrane, or what is believed to be a membrane, 
Storch has isolated and analyzed. He finds it to consist of 
94 per cent of water and 6 per cent of proteid. 

The reasons deduced by Storch are strong; and the behavior 
of cream and butter renders it probable that there is such a 
membrane enveloping each globule of fat. 



CLASSES OF FATS 13 



CLASSES OF FATS 



There are two great classes or groups of fats present in the 
butter, namely: 

(i) Volatile and Soluble, 

(2) Non-volatile and Insoluble. 

It was previously stated that little is known concerning the 
way in which the fatty acids are combined with glycerine in the 
milk; but, for the sake of convenience, the fats will be referred 
to as if they existed as separate glycerides of fat. 

The terms " Volatile " and " Non- volatile " are applied to 
the glycerides of fat, or to the fats as they exist in butter. Strictly 
speaking, this is not proper, as they do not assume the volatile 
characteristics until the glycerine separates from the fatty acids; 
it is only then that the latter become volatile. 

Volatile Fats. — The first group, or the volatile fats, include 
butyrin, caproin, caprylin, caprin, and laurin. Butyrin is the 
one present in the largest proportion. Laurin and caprin are 
partially non- volatile. Butyrin is the most important fat 
belonging to the volatile group. It is the most important quan- 
titatively and also qualitatively. So far as is known, butyrin 
is the least stable of any of the butter-fats. Under normal con- 
ditions, so long as the fatty acid remains in combination with the 
glycerol, it is neither volatile nor soluble in water; but as soon 
as separation takes place, due to the action of micro-organisms, 
or to the effect of light and air, it becomes volatile, and escapes 
in the form of gas. 

It is also claimed that these volatile fats have the special 
properties of absorbing odors and gases to a greater extent than 
any of the other fats. This absorption takes place when fat 
comes into contact with the undesirable taints. For this reason 
it is essential that milk, cream or butter be kept away from any 
foreign, undesirable odors. These taints may also be imparted 
to the fat before the milk is drawn. If the cow is fed on unde- 
sirable food, such as turnips, onions, garlic, etc., the milk from the 
cow assumes undesirable characteristic flavors which can easily be 
recognized in the finished product. On the other hand, such 



14 BUTTER-MAKING AND COMPOSITION OF MILK 

foods as well-cured clover hay and bran seem to impart desirable 
flavors to milk and butter. 

The presence of these volatile fats in butter is quite uniform, 
and is a distinguishing feature of pure butter-fat. The detection 
of adulteration of butter with foreign fats is based chiefly upon 
the presence of these volatile fats. The characteristic desirable 
flavor of butter is also believed to be due to the presence of the 
volatile fats. The volatile fats vary but slightly during the dif- 
ferent seasons of the year. They are present in the greatest 
proportion during the spring and early summer months, when 
cows are fed on grass, and also during the early stage of the period 
of lactation. They decrease gradually as the lactation period 
advances. 

Volatile fats comprise about 8 per cent of the total fats in 
milk. 

Non- volatile Fats. — This group constitutes about 92 per cent 
of the total fats in butter. Chemists now agree that palmitin, 
stearin, olein, and myristin are the most important ones to be 
considered, as will be seen from the table quoted from Richmond. 

These non- volatile fats are of special importance, as the 
relative amount of each of these fats largely causes the variation 
in the hardness and softness of the butter and butter-fat. The 
melting-point of these different fats varies according to the dif- 
ferent investigators : olein is a liquid at ordinary temperatures and 
melts at about 41° F.; stearin, on the other hand, has a melting- 
point of about 150° F.; palmitin also has a high melting-point, 
namely, about 142° F.; myristin melts at about 129° F. 

Olein has been found to be present in the greatest propor- 
tion during the spring, when cows are fed on grass. When 
cows are fed on normal dry food, as in the winter time, it is present 
in a much less degree. This, together with the small increase of 
volatile fats, is the cause of the softer butter so frequent in the 
spring. The hardness of the butter in the fall or winter is due 
chiefly to the presence of a slightly increased amount of the fats, 
with a high melting-point, as mentioned above. 

From what has been said above, one is led to believe that, 
by melting a sample of butter which contains these different 



COMPOSITION OF BUTTER-FAT 15 

fats, the fats with a low melting-point would melt first, and leave 
the remainder in an unmelted condition. Such is not the case. 
Butter-fat in this respect behaves a good deal like different 
metals with different fusing-points. When they are melted and 
mixed together, cooled and then remelted they assume a common 
melting-point. Butter-fat behaves in the same way. It melts 
at a temperature of 91° to 96° F. 

As the body temperature of cows (about 101° F.) is above this 
temperature, the fat globules are present in the milk in liquid 
form when it is first drawn. A peculiarity about these fat- 
globules in milk is that the milk and fat may be cooled below the 
melting-point of the fat of butter without the fat-globules in milk 
being soHdified. It requires a temperature of between 60° and 
78° F. before the fat-globules in milk begin to soKdify. When 
these small fat-globules are caused to unite, as during the churning 
process, they solidify at a higher temperature. This behavior of 
the fat in milk evidently must be due to a relative change in the 
position of the molecules of fat during the process of cooling and 
warming. No definite explanations, so far as is known, have been 
given for this condition of the fat. 

The non-volatile fats found in butter-fat are practically the 
same as those found in other animal fats. 

Composition of Butter-fat. — In his " Dairy Chemistry," 
Richmond gives the following composition of butter-fat, repre- 
senting the mean results obtained by different observers: 

Per Cent 

8S 
60 

55 



r Butyrin 3 

8 per cent volatile \ Caproin 3 

l- Caprylin 



92 per cent non-volatile. 



Fat I j' Caprin 1.9 

Laurin 7.4 

Myristin 20 

Palmitin 25 

Stearin i 

Olein 35 

Richmond also gives the percentage of glycerine and fatty 
acids in each of the different fats, as follows: 



16 



BUTTER-MAKING AND COMPOSITION OF MILK 



Butyrin 3-85% yielding 3.43% fatty acids and 

Caproin 3.60 yielding 3.25 fatty acids and 

Caprylin 55 yielding .51 fatty acids and 

Caprin. 1.9 yielding 1.77 fatty acids and 

Laurin 7.4 yielding 6.94 fatty acids and 

Myristin 20.2 yielding 19.14 fatty acids and 

Palmitin 25.7 yielding 24.48 fatty acids and 

Stearin 1.8 yielding 1.72 fatty acids and 

Olein 35 yielding 33.60 fatty acids and 

100 94-84 



1.17% glycerine 
glycerine 
glycerine 
glycerine 
glycerine 
glycerine 
glycerine 
glycerine 
glycerine 



12.53 



PROTEIDS (ALBUMINOIDS) 

The proteids of milk are present partly in solution and 
partly in suspension. They are present in a very complex 
chemical form. Some of the chemists reckon as many as eight 
different albuminoids or proteids in milk. Duclaux claims that 
there are only two kinds of albuminoids, the coagulaUe and non- 
coagulahle casein. He has, by the use of a fine filter, been able to 
separate the fat and the coagulable from the rest of the serum. 
The amount of coagulable casein is claimed to vary considerably, 
and seems to depend upon the amount of lime phosphate present. 
The filtrate which Duclaux obtained from filtering the milk was 
clear and colorless, which proves that the removal of the casein 
was quite complete. In order to remove casein from milk, a 
special filter (Chamberland) is employed. Owing to this fact, 
we may consider the casein to be present in suspension or semi- 
solution. Noted chemists, such as Babcock, Van Slyke, Duclaux, 
Storch, Hammarsten, Ritthausen, and Richmond, disagree upon 
the number of albuminoid substances found in milk, and upon the 
chemical behavior of each. 

For all practical purposes it is safe to mention two, namely, 
(i) casein, and (2) albumen. Those two substances, as all agree, 
are present in milk, and constitute practically all the albuminoids 
in milk. But after these two have been separated from milk a 
slight precipitation can be obtained by treating the filtrate with 
alcohol. This has been called albumose and also lactoglobulin. 
From this resultant filtrate a V£ry small amount of material 
containing nitrogen can again be separated. Dr. Babcock 



CASEIN 17 

has obtained a substance from milk called fibrin. These 
latter substances, however, are present in minute portions, and 
are believed by some of the best scientists to be the same as the 
albumen. Their presence in the filtrate is due to incomplete 
precipitation of the albumen in the first place. 

Casein. — Casein is by far the most important of all of the 
albuminoids. It is the substance which forms the curd in cheese- 
making. In fresh milk, as is now understood, it is in chemical 
combination with lime salts. It is on this account that fresh milk 
shows the amphoteric reaction, which will be explained under 
the " Properties of Milk." The coagulation of casein by the 
addition of rennet or dilute acids is thought to be due to this 
union between the casein and lime. Fleischmann refers to this 
as the " caseous matter " of milk. The viscosity of normal milk 
is beHeved to be due in a large measure to this condition of casein 
in milk. It causes the casein to be present in a colloidal condi- 
tion. When milk coagulates by natural or by artificial means, 
the union between the casein and Hme phosphate is largely 
broken. 

Casein and albumen differ in composition, in that the casein 
contains phsophorus and less sulphur than does albumen. 
Fleischmann maintains that a substance called nuclein is asso- 
ciated with casein, and is not found in albumen. 

Casein is precipitated by the use of rennet and dilute acids, 
and coagulates spontaneously, due to the acid formed in the milk. 
The precipitates formed by the use of different precipitating 
agents are not ahke. The curd coagulated by rennet contains 
more fat and calcium phosphate than the curd which is precip- 
itated by dilute acid or by the spontaneous souring of the milk. If 
milk stands at air temperature for any length of time after milk- 
ing, the caseous matter (or the nitrogenous matter combined with 
lime) tends to separate. The caseous matter of milk is not com- 
pletely precipitated by heat, although heat partially destroys the 
union between the casein and lime. This largely destroys the 
action of rennet. Instead of getting a smooth solid coagulum, a 
more flaky precipitate is obtained. For this reason milk for 
cheese-making should not be heated to a high temperature. By 



18 BUTTER-MAKING AND COMPOSITION OF MILK 

heating milk in a glass flask to a high temperature, and letting it 
stand for a time, it will be found that a mineral precipitate has 
settled to the bottom. This precipitate is believed to be a lime 
phosphate, which, previous to heating, was combined with the 
casein of the milk. By adding calcium chloride (CaCb) to milk 
which has been heated, its normal condition towards the action of 
rennet is again restored. 

Albumen. — If the casein is removed from the milk by pre- 
cipitation, and then filtered off, the filtrate will contain a sub- 
stance which will precipitate when boiled. This is albumen, 
and is similar in character to albumen from the white of an 
egg. It differs from casein in that it is not precipitated by 
rennet or acids, but precipitates on heating. It does not contain 
any phosphates, but contains a comparatively large amount of 
sulphur. 

As the albumen is soluble in rennet and dilute acids, it can 
readily be seen that it is retained in the whey obtained in cheese- 
making. When albumen is present in small quantities, as it is in 
normal milk, heating does not completely precipitate it, unless 
the casein or curd is first removed. If, on the other hand, 
albumen is present in excess, as is the case in colostrum, the major 
portion of the albumen is precipitated when heat is applied with- 
out first removing the casein. 

Sugar. — Milk-sugar occurs in milk to the extent of about 5 
per cent. It varies very little in quantity, seldom falling below 
3I per cent and seldom rising above si per cent. It occurs in 
solution, and is not found elsewhere in nature. 

Milk-sugar is the most unstable component of milk; its 
decomposition is brought about quickly and easily by the action 
of micro-organisms. If these could be entirely excluded from the 
milk, it would keep for an almost indefinite length of time. As it 
is impossible under practical conditions to entirely exclude 
organisms from the milk, the only way to retard and prevent the 
growth of germs and thereby prevent the changing of the sugar 
into other products, is to cool the rnilk to a low temperature 
(50° F.), or to heat the milk to a sufficiently high temperature 
(180° F.) to destroy most of the germs. According to Van Slyke 



ASH 19 

and Hart, the decomposition of the caseous matter produces free 
casein. When about .5 per cent acid has developed in the milk, 
the free casein combines with the acid and forms casein lactate. 
The chemical composition of milk-sugar is C12H22O11+H2O. 
Were a perfect decomposition of milk-sugar into lactic acid to 
take place, the following equation would represent the change : 

(Milk-sugar) (Lactic acid) 
C12H24O12 =4C3H603. 

Such an ideal change, however, never takes place. In such a 
case, one gram of milk-sugar should produce one gram of lactic 
acid. In a number of experiments carried on by one of the 
authors of " The Analysis of Cream during Different Ripening 
Stages,"^ the highest amount of acid produced from one gram of 
milk-sugar was .8 of a gram. This indicates that there are 
always accompanying by-products produced, besides lactic 
acid, when milk-sugar is being decomposed in cream or milk. 
The sourness of milk is due to this change. The by-products 
which accompany the production of lactic acid are many 
and various. The most important ones are gases of different 
kinds, such as carbonic acid gas (CO2); marsh gas (CH4); 
hydrogen (H); and nitrogen (N.) Small amounts of alcohol, 
formic, acetic, and succinic acids are said to be normal 
accompanying by-products also. These by-products may also 
partially result from the breaking down of some of the other milk 
components. 

As milk-sugar is in perfect solution, it follows the water of 
milk, and in cheese-making nearly all of it passes into the 
whey. Commercially and chemically it is prepared from whey. 
It is a white, not very sweet powder, and is used for medicinal 
purposes to dilute pure, powerful drugs. It is also used exten- 
sively in the preparation of modified milk. 

Ash. — The ash of milk is present in very small quantities, 
and when viewed from such a standpoint it may first seem to be of 
small importance. On account of the effect of the mineral con- 

^ Thesis, I. S. C, Ames, la. 



20 BUTTER-MAKING AND COMPOSITION OP^ MILK 

stituents upon the properties of milk, it is one of the most impor- 
tant components of the milk. It exists partly in solution, and 
partly in suspension. Babcock maintains that about one-third 
of the usual ash constituents are in suspension, and that they 
consist chiefly of lime phosphate. 

All of the minerals in milk consist chiefly of potash, lime, 
soda, magnesia, and iron, combined with phosphoric, hydro- 
chloric, sulphuric, and carbonic acid. Calcium phosphate 
constitutes about one-half of all the ash constituents. They 
are named above, in order, according to the extent to which 
they occur in milk. 

Gases of Milk. — These do not normally exist in milk to such 
an extent as to enable chemists to determine them quantita- 
tively, but they are of great importance, owing to the effect they 
have upon the quality of the milk, viewed in the commercial 
sense. 

Gases in milk m.ay be divided into two classes according to 
their origin; namely, (i) those imparted to milk before milking 
and (2) those which are later formed and absorbed in milk. 

(i) When freshly drawn, milk has a characteristic odor, 
which seems to be normal to all fresh milk. The gases which 
cause this odor are very volatile, and by cooling and stirring the 
milk can, to a large extent, be eliminated. The amount and 
kind of taints existing in milk, immediately after it has been 
drawn, largely depend upon the food which the cow has been 
fed. Turnips, onions, and garlic, when fed to cows a short time 
before milking, cause undesirable gases or taints to exist in the 
milk. Good hay, bran, and good grass produce milk of superior 
quahty, containing no odors excepting those which are natural to 
all milk when first drawn. 

The milk yielded by cows pasturing in the Alps of Switzer- 
land is said by tourists to possess a pecuhar, not undesirable, 
spicy odor and flavor. It is maintained by the native people in 
Switzerland that the pecuhar flavor of the Emmenthaler cheese 
cannot be developed anywhere else in the world. This flavor 
they believe to be due to the kind of vegetation the cows feed 
upon in the Alpine pastures. In Denmark, the poor people 



GASES OF MILK 21 

who do not own much land, graze their cows along the roads 
where weeds of different kinds grow. Milk from such cows has a 
pecuUar characteristic odor or taint. In this country it is a 
common occurrence to find that milk delivered by patrons who 
keep their cows on timber-land pastures has a peculiar weedy 
odor. Especially is this true in the fall or late summer. If such 
milk is heated to i6o° to i8o° F., and stirred occasionally, some of 
these taints pass off. The addition of a small amount of saltpeter 
will improve the flavor of milk where such foods as turnip and 
sugar-beet tops are fed. This remedy is often applied to milk in 
Canadian cheese factories, during the fall of the year when turnip 
tops are fed, and also in Germany during the period of the feeding 
of sugar-beet tops. 

Too much emphasis cannot be placed upon the food that 
the cows receive. While it is true that much of the desirable 
aroma and flavor in butter is due to bacterial growth, the kind 
of food fed to cows is not without significance. It is a well-known 
fact that districts such as Normandy and Denmark, which have 
become fam.ous for their high quality of dairy products, have the 
best of pasture and winter feeds. 

Besides the kind of food, some physiological disturbances of 
the cow m.ay cause abnormal taints in milk. 

(2) Gases or taints which are formed in the milk or absorbed 
by it are due to fermentation and absorption respectively. The 
former cause will be considered in a separate chapter, and the 
latter cause needs little explanation. It is a well-known fact 
that milk and most of its products have the special property 
of absorbing odors which may be present in their surroundings. 
For this reason, milk, as well as other dairy products, should at 
all times be kept in clean utensils and pure surroundings. 

Taints appearing in milk immediately after milking are due to 
absorption within the cow. Taints that develop on standing are 
due to bacterial growth in the milk, or to absorption from impure 
surroundings. In the prevention and removal of taints from 
milk the first step is to remove the cause, and the second to 
eliminate as many of these taints as possible by a process of 
aeration or pasteurization. 



22 BUTTER-MAKING AND COMPOSITION OF MILK 

Coloring-matter. — It is not known of what the coloring- 
matter in milk consists. A substance named lactochrome has 
been found in milk. So far as known, this coloring-substance is 
closely associated with the fat called palmitin. The amount of 
coloring-matter varies during the different seasons of the year. 
It also varies according to the different breeds. During the 
spring of the year, when cows are first put on grass, the color of 
of the butter-fat is always higher than it is during the latter por- 
tion of the summer. During the winter, the fat in milk is quite 
pale. By feeding the cows some succulent feed in the winter, 
such as silage, carrots, and beets, the color of the butter-fat is 
rendered much higher. 

From this it would seem that the change in the color of the 
fat with the different seasons, and with the food given, is closely 
associated with chlorophyl, the coloring-matter of grass. 

Other Constituents of Milk. — It is said that constituents 
such as citric acid, urea, nuclein, lecithin, and galactase are 
present. Babcock maintains that he has discovered a sub- 
stance named fibrin. This seems to be similar to the nuclein 
mentioned by Fleischmann, if not the same. But as these 
substances are present to a very small extent, citric acid, urea, 
and fibrin being present to the extent of .12, .007, and .0002 
per cent respectively (Fleischmann and Babcock) , they are of 
little importance. 



CHAPTER II 
MILK SECRETION 

The Mammary Gland as a Secretory Organ.— The mammary 
gland of females belonging to the order of mammalia secretes a 
fluid known as milk. This substance is strictly a secretory 
product. There are two kinds of glands present in the animal 
body, viz., the excretory and the secretory. Generally speaking, 
an excretory gland is one which receives or absorbs the waste 
matter of the body, and causes it to be carried off without causing 
any marked change to take place in the substance excreted. 
A secretory gland is one in which the raw material is obtained 
from the blood and then manufactured into a special different 
product within the gland itself. As an example of a secretory 
gland, the milk-gland of the cow's udder is an apt illustration. 
The glands in the mouth secreting saliva, and those in the walls of 
the stomach secreting the digestive fluids, are also secretory 
glands. 

Internal Structure of Cow's Udder. — The cow's udder is 
composed of two separate glands, the right and left halves. 
These two glands are distinctly separated from each other by a 
fibrous tissue running longitudinally. This fibrous partition 
extends along the abdomen in front, and back to a point between 
the thighs of the cow. It also serves to hold the cow's udder in 
place. There is no connection at all between the right and left 
glands, and consequently milk cannot be drawn from the left 
side over to the right, and vice versa. 

Each of these right and left halves is again divided into two 
parts, thus making the cow's udder appear to be divided into 
quarters. The cow's udder may then be said to consist of two 
glands, one on each side, and four '' quarters," two to a gland. 
The division between the two quarters of a gland is not complete ; 

23 



24 



MILK SECRETION 



that is, there is enough connection between the two to allow 
a portion of the milk to be drawn from the rear quarter through 
the front teat on the same side, and vice versa. 

The milk-glands proper are located near the abdomen and 
extend a trifle downwards into the udder. The remainder of the 



GLAND-LOBULE 
ALVEOLI 




Fig. 2.— Schematic figure siiowing cross-section of cow's udder; and also 
enlargement of epithelial cells in alveoli when cow is giving milk (i). Each 
alveolus is surrounded with a membrane called tunica propria. Cell nuclei 
not shown. When cow is in milk they are also enlarged. When not the 
epithehal cells are flat and the nuclei small and spindle shaped (2). 



udder is filled with ducts, fibrous and connective tissue, muscle, 
nerves, and blood-vessels, the whole udder assuming a sort of 
spongy and open condition. 

The teat is simply a cyhndrical-shaped body, with a hollow 
tube extending down through the center of it. At the bottom 



INTERNAL STRUCTURE OF COW'S UDDER 25 

of this opening, or at the end of the teat, there is a sphincter 
muscle, which in some cases is drawn up very tight, while in 
other instances it is so loose that it will not prevent the milk from 
escaping. In case the muscle is so tight that the milk can be 
drawn only with difficulty, it may be relaxed a trifle by inserting 
a small, smooth wooden plug. This will usually dilate the open- 
ing sufhciently, so that the milk may be drawn with comparative 
ease. In some instances this muscle is so tight that it is necessary 
to relax it by the use of a sharp knife. This, however, should be 
done with surgical skill; otherwise the whole muscle is likely to be 
so injured as to cause the milk to leak away at all times. 

The upper part of this canal in the teat connects with what 
is called the milk-reservoir. The size of this reservoir varies in 
different cows. The average capacity of this milk-cistern is 
about one pint. The opening from this reservoir into the teat 
is also guarded with a muscle. Over this muscle the cow has 
little control; over the muscle at the lower end of the teat she 
has no control whatever. 

Opening into the sides and top of this reservoir are a large 
number of tubes, which are called milk-ducts. These milk-ducts 
extend from the reservoir up into the milk-gland. They radiate 
in all directions, divide and subdivide, so as to form a very large 
number of small tubes. These milk-ducts are surrounded with 
fibrous mxUscular tissue, nerves, and blood-vessels. They are all 
guarded by a special muscle at the junction with the main milk- 
ducts, from which they radiate. These m.uscles are so inti- 
mately connected with the nerves and muscular system of the 
cow that she is able to open and close them at will. There are 
very few cows that are not able to hold up their milk during 
nervous and exciting periods. It is a common occurrence for a 
milker to get only a small part of the milk from a cow; this small 
amount is the portion which is present in the teat and milk- 
reservoir. Some cows are able to hold up this milk also, but the 
majority of cows cannot perfectly control the muscle which 
guards the entrance to the teat. The milk which is present in 
the milk-ducts and which has to pass through these junctions 
referred to above can be held up by most cows at will. 



26 MILK SECRETION 

All of the small milk-ducts end in small sac-like bodies, each 
of which is called a gland-lobule or ultimate follicle. The gland- 
lobules enclose numerous individual microscopical bodies called 
alveoli or acini; these are the organs which possess the proper 
secretory functions. Their outer covering is a membrane called 
the tunica propria; within this there is an intermediate layer of 
cell- tissue, and an inside layer composed of cells, which are named 
the epithelial cells. These epithelial cells within the alveoli are 
supplied with blood from the cow's system. During lactation 
they assume a different form, swelling and extending into the 
cavity of the alveoli when the cow is yielding milk abundantly, 
and when she is not in milk the alveoli are flat. A certain 
number of alveoli are tributary to one particular duct leading 
from the gland-lobule into still larger milk-ducts. 

Each aggregation of gland-lobules, tributary to one milk- 
cistern, constitutes a lobe, and may be Hkened to a side branch 
of a bunch of grapes. Each separate grape may represent a 
gland-lobule. The seeds within the grape, if we imagine each 
seed to be hollowed out and lined with small colimin-like bodies, 
may be likened to the alveoli. These column-like bodies would 
then represent the epithehal cells. The stem leading from each 
individual grape may represent the small duct which carries the 
milk on to the larger ducts. The main stems of the bunch may 
represent the larger ducts that enter into the milk-reservoir. The 
air which everywhere fills the openings or interstices of the various 
parts of the bunch of grapes may be hkened to the fibrous fatty 
tissue between the alveoh and the lobules of the gland. 

Theories of Milk Secretion. — ^Although the theories of milk 
secretion have been studied considerably, many things in this 
connection are not well understood. Previous to the year 
1840 it was thought that the only function of the milk-gland 
was to filter the milk as it transuded from the blood. It was 
supposed that the quahty and quantity of milk depended entirely 
upon the food. The theory has also been advanced that the 
major portion of the milk constituents is a decomposition of 
the product of the lymph bodies of the blood. It was believed 
that the lymph bodies were a source of nourishm.ent to the fetus. 



THEORIES OF MILK SECRETION 27 

and that the calf received its nourishment from the same source 
after it was born as it did previous to birth. It was supposed that 
after the birth of the calf the opening on the uterus through which 
the food was supplied was closed, and that a new opening was 
formed in the milk-gland. These two theories have now been 
practically overthrown. It has been demonstrated that the 
major portion of the milk is formed within the milk-gland. The 
fat, casein, milk-sugar, and part of the albumen are supposed to 
be formed in the udder. This conclusion is substantiated by the 
fact that these substances do not appear in the blood, at least not 
to such an extent as to warrant the assumption that they are not 
manufactured in the cow's udder. The total amount of fat in 
the blood of the cow would hot equal the fat in the milk from one 
milking. 

By some it is maintained that the substances in milk which 
are found in solution may be transuded directly from the blood. 
Here again milk-sugar is found to be in perfect solution in the 
milk. But this substance can be found nowhere in nature 
besides in milk. It is not present in the blood of the animal; 
consequently it must be manufactured within the gland itself. 
The water of milk, and the ash constituents which are in solu- 
tion, are probably transuded directly from the blood. No 
attempts have been made to determine definitely how casein and 
albumen are formed within the gland. 

According to the theory which has been advanced, the fat is 
formed by the breaking down of the epithelial cells. When the 
breaking-down process is completed, the transformed cells appear 
at the opening of the alveoli in the form of distinct fat-globules. 
This is supposed to be the origin and formation of fat-globules 
in milk; so it may be said that so far as known the fat is the 
result of a breaking down of degenerated epithelial cells. 

Dr. Bitting asserts that the formation of milk solids in the 
cow's udder is probably due to a metabohc process rather than 
to a degenerative. ColHer found that a cow giving a normal 
amount of milk would secrete about 136,000,000 fat-globules 
per second. He also suggests that a cow secretes about 5 pounds 
of milk solids per day. As a cow's udder weighs only about 2^ 



28 



MILK SECRETION 



pounds, the whole udder would have to be renewed twice daily. 
This is not consistent with our presi nt knowledge of tissue 
building. 

The chief incentive to milk secretion is maternity. As soon 
as the young mammal is born the blood which went to the 
uterus to supply the calf is turned toward the udder instead. 




Fig. 3. — A schematic figure showing the course of the artery leading to the 
mammary gland and the veins returning to the heart. The light-colored 
lines represent arteries and the dark-colored lines the veins. (From Bitting, 
Twelfth An. Report, Indiana.) 

As soon as this current of blood begins to flow, all of the blood- 
vessels and capillaries in the cow's udder swell. This causes the 
minute blood-vessels or capillaries which form a network in the 
walls of the alveoli to swell, and their swelhng stimulates the 
epithelial cells to activity. 

Conditions Affecting Secretion of Milk. — There are a great 
many conditions which affect the milking capacity of a cow. 
These conditions may be conveniently grouped into two classes 



CONDITIONS AFFECTING SECRETION OF MILK 29 

according to their causes: (i) conditions which are controlled 
largely by man, and (2) conditions which are inherent in the cow. 

1. Some of the chief conditions which reduce the secretion of 
milk and are largely controlled by man are: improper care 
and treatment of the cow, lack of proper food, incomplete and 
and improper milking, irregularity, and long periods between 
milkings. Pregnancy, nervousness, or excitement of any kind 
affects the proper working of the milk-glands considerably. 
These latter causes, however, are not always controlled by man. 

2. Without denying the influence of those conditions men- 
tioned above, the conditions which chiefly affect the milk- 
secreting capacity are inherent. It does not matter how much 
good care and food a cow receives, if she does not possess these 
inherent necessary quahties. As was mentioned before, the 
milk-secreting capacity depends upon the number of gland- 
lobules, the amount of blood which is supplied to these secretory 
parts, and the capacity of the cow to digest and assimilate food, 
and possibly upon a stimulating body fluid not yet well under- 
stood. 

The number of gland-lobules is believed to increase until the 
cow is about seven years old. The milk-secreting glands are 
present only in a rudimentary form, until the cow has had 
her first calf, or is well advanced in the first stage of pregnancy. 
The gland-lobules then increase in number up to the age of about 
seven. The relative number of lobules in the cow's udder can 
only be approximately ascertained. The size of the udder in 
some measure indicates this. A cow with a large flexible udder is 
usually a good milker, due to the fact that a large udder usually 
contains a large number of gland-lobules. 

The amount of blood which is turned through the cow's udder 
to supply the milk-secreting cells may be approximately ascer- 
tained by the size of the blood vessels. The blood from the heart 
enters the udder near the region of the hips. It then passes down 
through the udder, along the abdomen just beneath the skin, 
until it reaches a point about midway between the flank and the 
girth. At this place it penetrates the abdominal wall and enters 
the thorax. The place at which the blood penetrates the abdom- 



30 MILK SECRETION 

inal wall may be felt with the finger. It is supposed that the 
size of this hole is in some measure indicative of the milk-produc- 
ing capacity of the cow. This opening in the abdominal wall is 
called the milk-hole or milk-fountain. Large irregular veins are 
considered a much better indication of good milking properties 
than small straight veins. 

The formation of gland-lobules is entirely inherent in the cow. 
The only way that these may be increased is through selection 
and breeding. The amount of blood which passes through the 
cow's udder is also largely inherent, although this may in a small 
measure be affected by the amount and quality of food given to 
the cow. It should at all times be remembered that a cow is not 
a mere receptacle into which so much food can be introduced, and 
from which so much milk can be drawn. After giving due credit 
for the influence of all other conditions, we must still recognize 
that the inherent conditions affecting the secretion of milk are 
the most important. 

External Appearance of the Udder. — A cow's udder should be 
well and symmetrically formed. It should be square and wide, 
and extend well along the abdomen of the cow, and back up 
between the thighs. When the udder is empty it should be soft 
and flexible. The teats should be medium large, be placed well 
apart, and point downwards. 

There should be little or no depression in the udder between 
the teats; that is, each quarter should not appear distinct and 
separate when viewed from the exterior. 

The cow's udder should be covered with fine, soft, downy 
hair. A light golden yellow is said to be indicative of a good 
quahty of milk. 

A firm, fleshy udder is undesirable. In the first place, it is 
not indicative of good milking quahties, and, secondly, such 
an udder is predisposed to inflammatory diseases. 

Milk-fever. — This is a common disease in fresh cows. It is 
due to a congested condition of the cow's udder. The decompo- 
sition products of the colostrum milk in the udder are absorbed by 
the blood, and produce the characteristic symptoms of milk-fever. 
Dr. Peters, of the Nebraska Experiment Station, says that a good 



MILK-FEVER 31 

and simple remedy for a diseased udder is to pump it full of air. 
This can be accomplished with an ordinary bicycle pump. After 
some air has been pumped in, the cow's udder should be worked or 
massaged with the hand so as to cause the air to pass through 
the quarter. He claims that the udder can thus be restored to its 
normal condition very quickly, thereby preventing and even 
curing milk-fever. In case the udder is caked very badly, apply a 
hot poultice. Small five- or ten-pound bags filled with bran 
and kept hot will prove very satisfactory. A compress consisting 
simply of a piece of heavy cloth is also used. It should be put 
on so that it lifts up the entire udder, and tied over the back of 
the cow. Straw should be put underneath it on the back so that 
the cord will not injure the animal. 



CHAPTER III 
PROPERTIES OF MILK 

Color. — The coloring matter of milk is associated with the fat. 
According to extensive investigations, made by Eckles and 
Palmer at the Missouri Station, this color is due to carotin^ so 
called because it is the coloring matter of the carrot. It is found 
in green plants and is closely associated with the chlorophyl, 
which hides its presence. It is not manufactured by the animal. 
Animals which produce milk rich in fat, in the form of large fat- 
globules, possess the ability to utilize this coloring matter to a 
greater degree than do animals which produce milk having a lower 
fat content and smaller fat-globules. This explains the downward 
gradation of the color of the fat in the milk as we pass from the 
Guernsey and Jersey to the Shorthorn, Ayrshire and Holstein 
breeds. 

Flavor. — Milk has a sweet flavor, and a faint odor. Fresh 
milk has a peculiar taste and odor, which pass off when it is 
exposed to the air. The flavor is affected by foods and con- 
ditions of the cow, as mentioned under " Abnormal Milk." 

Opacity of Milk. — Milk is opaque, except when seen in very 
thin layers; then it is sHghtly transparent. The opacity of milk 
is due to the presence of the fat and nitrogenous matter. When 
these substances are filtered away on a fine clay filter (the Cham- 
berland), the filtrate which passes through is clear and trans- 
parent. It has been maintained that the fat in milk is the chief 
cause of its opacity, and that the percentage of fat could be 
determined according to the degree of opacity and transparency 
of milk with an instrument named pioscope ; but it was soon found 
out that the size of the fat-globules, as well as the number, had 
considerable influence upon the degree of opacity of milk. For 
that reason, this method of determining the amount of fat in 

32 



CHEMICAL REACTION OF MILK 33 

milk was not reliable. The fat-globules themselves are said to be 
almost transparent, yet the color and opacity of milk is largely 
due to their presence. This characteristic may perhaps be 
explained by assuming that the fat-globules in milk deflect the 
light instead of allowing it to pass through them. 

After the fat has been removed, the milk still continues to 
be opaque. When the albuminoid matter has been removed 
and filtered off the filtrate becomes clear and transparent. 

Chemical Reaction of Milk. — Milk when fresh shows an 
amphoteric reaction, which means that it exhibits both an alkaline 
and an acid reaction when tested with litmus paper. It turns 
blue litmus paper red, and red htmus paper blue. This peculiar 
behavior of milk is said to be due to the caseous matter in the 
milk, which itself has an acid reaction, while the remainder of 
the serum has a slight alkaline reaction. By testing the reaction 
of fresh milk with a tenth normal alkali solution, and using 
phenolphthalein as an indicator, an acid reaction is obtained. 
After standing, milk soon becomes distinctly acid, due to a 
change of the milk-sugar into acids, chiefly lactic acid, through 
the action of micro-organisms. Richmond maintains that the 
ami.photeric reaction of milk has acquired a false importance, as he 
believes that the neutrality, as measured by the action of litmus 
paper, is not chemical neutrality. 

Specific Gravity of Milk. — By specific gravity of milk we 
mean the weight of the milk as compared to that of an equal 
volume of water at the same temperature. If a certain volume 
of water weighs looo pounds, an equal volume of milk at the 
same temperature and under the same conditions will weigh 
about 1032 pounds. Reducing the figure to a basis of i, as is 
always done, the comparison between the two equal volumes of 
water and milk will be i and 1.032. This latter figure represents 
the average specific gravity of normal milk. 

It can be readily seen that the correct specific gravity can 
be obtained only at one given temperature, for, as the tempera- 
ture of the substance becomes higher, the density of it grows less, 
and consequently the specific gravity will be less. The tempera- 
ture at which the lactometers are standardized is 60° F. 



34 PROPERTIES OF MILK 

The specific gravity of milk will also vary according to the 
relative variation in amounts of the different components. If a 
sample of milk is rich in solids not fat, as, for instance, skimmed 
milk, the specific gravity will be high and usually between 1.033 
and 1.037. If the sample of milk is rich in fat, as, for instance, in 
cream, the specific gravity will be less. 

The specific gravity of milk is lessened by the addition of 
water. Owing to this fact it was first thought that adulteration 
of milk with water could be detected by testing its specific grav- 
ity. But this method was soon found to be erroneous, as it is 
possible to take cream away and add water in such a proportion 
as not to alter the specific gravity of the sample. A low specific 
gravity may, however, cause the suspicion that the milk has 
been adulterated, and the test for water adulteration can be 
supplemented by testing it for fat. 

As has been mentioned before, the lactometer reading should 
be taken at 60° F. If the temperature of the milk is above or 
below, corrections must be made. The amount of correction 
which will give approximate results is .1 of a degree added to the 
lactometer reading for every degree Fahrenheit of tempera- 
ture above 60° F., and .1 of a degree subtracted from the lactom- 
eter reading for every degree of temperature below 60° F. The 
temperature of milk when tested for lactometer reading should 
never go any lower than 10° below 60°, nor any higher than 10° 
above 60°. This would leave the range of temperature between 
50° and 70° F. 

In chemical laboratories, the specific gravity of milk is usually 
determined by the use of a picnometer. 

In practice there are three instruments in general use for 
determination of lactometer reading, or specific gravity, viz., 
Quevenne lactometer, New York Board of Health lactometer 
and the ordinary hydrometer. The Quevenne lactometer is the 
one that is used chiefly in creameries. The graduation of each 
one of them is given in the accompanying diagram. It may be 
seen from the figures that in order to change the Quevenne 
lactometer reading into specific gravity, all that is necessary is 
to add 1000 and divide the sum by 1000. In changing the 



NATURAL SEPARATION OF CREAM AND MILK 



35 



specific gravity into lactometer reading the reverse process will 
give correct results. 

The hydrometer gives the specific gravity directly. The 
Board of Health lactometer has a special graduation. When 
this lactometer was devised it was thought that 1.029 was the 
minimum specific gravity of un- _ _ . 

adulterated milk. The scale on this 
lactometer was made from zero 
to 1 20, zero marking the point which 
represents the specific gravity of 
water, namely, i, while 100 is the 
point which is assumed to represent 
the least specific gravity of milk, 
1.029. If the specific gravity of a 
certain sample of milk fell to 90, it 
indicated that there was 10 per cent 
of water present. If it fell to 80, 
it indicated that there was 20 per 
cent of water, etc. 

In order to calculate the total 
solids, and solids not fat, of milk, 
it is necessary to know its lactometer 
reading, and the percentage of fat 
in it. Knowing these factors, by 
the use of the following formula 
given by Farrington and Woll, and 
deduced from Fleischmann's work, 
the total solids, and solids not fat, 
can be found. 



1.010 



1.015- 



1.020 -- 



1.025 



1.030 - 



1.035- 



S N Q 

"S" Specific Gravity Scale. 
"N" New York State. 
"Q" Quevenne. 

Fig. 4. — Comparative gradua- 



tion of lactometer stems. 



Sohds not fat = J lact. reading+ .2 times the fat. 
Total solids = fat + solids not fat. 



Natural Separation of Milk and Cream. — ^When milk is 
allowed to stand quietly for a short time, a layer having a rich- 
yellow color comes to the surface. This is the cream, and con- 
tains most of the fat. This separation is due chiefly to the 



36 PROPERTIES OF MILK 

difference in weight, or specific gravity, of the fat-globules and 
the serum. The force which acts upon the globule of fat is the 
difference in weight between the fat-globule and the serum which 
it displaces, minus the resistance with which it meets in its upward 
passage. This force is great in milk with a high degree of vis- 
cosity and slighter in milk of a limp and liquid consistency. 
While the addition of water to milk reduces its viscosity it also 
lowers its specific gravity. Hence, the so-called " dilution cream 




Fig. $. — Standardized milk. Showing the amount of cream on milk containing 
the designated per cent of butter-fat. (From Bui. 92, 111.) 

separator " has, generally speaking, little to recommend it. 
While the skim-milk may give a lower test we must remember 
that there is a greater quantity of it. Furthermore, it lacks the 
palatability and feeding value of undiluted skim-milk. But this 
is a point that need not be labored, since the hand separator has 
all but superseded the different methods of setting milk. 

In normal milk, the amount of fat left in the skimmed milk by 
natural creaming is about .4 per cent. The fat which is left in 
this skimmed milk is largely composed of very small globules. 
This is due to the fact that the resistant force on these small 
globules is equal to or greater than the buoyant force acting upon 
them. 



ADHESION OF MILK 37 

The completeness of natural skimming is to a certain extent 
based upon the mathematical law which is stated as follows: 
" The surfaces of two spheres are to each other as the squares of 
their diameters, and their cubical contents are to each other 
as the cubes of their diameters." The larger the globules are, 
the greater the surface is, and the greater the resisting force to 
which they are subjected. From the law stated it can be seen 
that as the size of the globule increases, the cubical content 
increases more rapidly than the surface. If a fat-globule were 
split up into smaller ones, there would be more surface exposed 
to the serum than was the case while the fat was present in one 
globule. 

For illustration, suppose two globules of fat to have diameters 
of 4 and 2 inches respectively. The squares would be 16 inches 
and 4 inches respectively; their cubes would be 64 inches and 8 
inches respectively. It will thus be seen, according to the 
law quoted above, that the larger globule has a surface only four 
times as great as that of the smaller one ; but the cubical content 
of the larger globule is eight times that of the smaller one. This 
illustrates why the large globules rise in cream more quickly than 
the small ones. In this particular instance the upward force the 
larger globule is subjected to is eight times greater than that of 
the smaller one, while the resistant force is only four times as 
great as that of the small one. 

Adhesion of Milk. — Normal sweet milk adheres to wood, 
glass, and metals to a greater extent than does water. Whole 
milk has greater adhesive properties than skimmed milk. A 
paper moistened with milk or cream makes a label that will stick 
to any dry object; the same paper moistened with skimmed 
milk has less adhesive power. The adhesive properties of milk 
are also due to the condition of the nitrogenous matter. This 
fact is made use of in painting and whitewashing. Slaked lime, 
when mixed with buttermilk, or milk of any kind, gives a white- 
wash which will remain on objects much longer than that made 
by mixing with water. 

Viscosity of Milk. — Milk is more viscous than water. The 
degree of viscosity of fresh milk varies chiefly with the tempera- 



38 PROPERTIES OF MILK 

lure and fat content. So far as understood, the lower the tem- 
perature, the greater the viscosity. Development of acid, and 
high temperature lessen the viscosity of milk. Pasteurized milk 
or cream is less viscous than the same milk or cream unpasteur- 
ized. This lack of body can again be restored by adding a Httle 
viscogen, as recommended by Babcock and Russell. Xt is not 
advisable to use it, however, as it does not add materially to the 
nutritive value of milk, but merely restores the body. 

The great viscosity of thick cold cream makes it difficult to 
churn, as most butter-makers have discovered. It adheres 
to the inside of the churn and simply rotates instead of being 
agitated. Cream that is cold and thick whips more easily than 
thin, warm cream, as the viscosity is so great that the air incor- 
porated cannot escape so easily. In ice-cream making, for the 
same reason, a greater yield is obtained by using cold, thick cream. 

Specific Heat of Milk. — The specific heat of milk is less than 
that of water; that is, it requires less heat to warm a definite 
amount of milk to a certain temperature than it does to heat the 
same quantity of water to the same temperature. It also takes 
less ice to cool the same volume of milk to a certain temperature 
than it does to cool the same quantity of water to the same tem- 
perature. The specific heat of milk is, according to Fjord, .94. 
The specific heat of cream is about .7. It varies according to the 
percentage of fat in the cream. The specific heat of butter is 
about .4. From these figures it will be seen that it takes less 
heat to warm milk, cream, and butter, and less cold to cool the 
same substances, than it does to heat and cool water; but it takes 
a longer time to heat or to cool milk, cream, and butter; that is, 
the milk, cream, and butter are not as rapid conductors of heat 
and cold as is water. 

The maximum density of milk is not reached, like that of 
water, at 4° C. but at about .3° C. The boiling-point of milk is a 
trifle higher and the freezing-point a trifle lower than that of 
water. 

Effect of High Heating (180° and above) on Properties of 
Milk. — The chief effects of heat upon milk may be summarized 
in the following headings: 



EFFECT OF HIGH HEATING ON PROPERTIES OF MILK 39 

(i) It destroys nearly all germs present in the milk. 

(2) It diminishes the viscosity, or body. 

(3) It drives off gases. 

(4) It imparts a cooked taste (especially if not heated and 
cooled properly.) 

(5) It precipitates some of the albuminoids and ash constit- 
uents. 

(6) It destroys the properties of enzymes present in 
milk. 

(7) It divides or spHts up the clusters and fat-globules. 

(8) It caramelizes some of the sugar. 

1. Destroys Nearly all Germs. — Heating milk to a tempera- 
ture of about 180° F. for ten minutes destroys most of the germs 
present. This is the temperature used in most creameries for 
pasteurization. The details concerning the different effects of 
temperature upon growth of germs properly comes under the 
heading of bacteriology, and will be referred to more in detail in 
the chapter on " Ferments in Milk." 

2. Diminishes the Visccsity, or Body. — Heating milk or 
cream diminishes its viscosity; that is, it lessens the body or con- 
sistency; and in cities where milk or cream is sold directly to 
consumers, heated milk appears as if it had been adulterated. 
This diminution in the body is claimed to be due to a breaking 
up of the clusters, and the fat-globules and the caseous matter. 
The chemical union of some of the calcium salts and the casein 
is altered or destroyed. 

The consistency of milk or cream can be restored by adding 
a substance named viscogen. Russell and Babcock ^ advise this 
method of overcoming the apparent defect caused by heating. 
It consists of making a strong solution of cane-sugar and mixing 
it with freshly slaked lime. This mixture is allowed to stand, 
and the clear solution coming to the top is the viscogen, which, 
when drawn off and used in the proportion of one part of viscogen 
to from 100 to 150 parts of cream, restores its body. This is 
due to the fact that viscogen causes the fat-globules to cluster 
together again, and the lime in the viscogen may combine with the 
^ Bulletin No. 54, Wisconsin, 1896. 



40 PROPERTIES OF MILK 

nitrogenous constituents in such a way as to aid in the restora- 
tion of the body of the cream or milk. 

Nearly all dairy laws forbid the addition of any foreign sub- 
stances to milk or cream. If viscogen is added, Babcock and 
Russell suggest tha. it be named visco-milk, visco-cream, etc. 
When the modification is made, no objection can be raised to its 
legitimate use. 

3. Drives off Gases. — When milk is heated, taints and gases of 
different kinds pass off to some extent. This is faciUtated by 



■^'•Y 

o*^^ 










Fig. 6. — Microscopic appearance of milk, showing natural grouping of the fat- 
globules. Single group in circle, highly magnified. (From Bui. 64, Wis.) 

heating and stirring in an open vessel. Many of these gases 
also escape when milk is aerated and cooled in a pure atmos- 
phere, 

4. Imparts a Cooked Taste. — When milk is heated to 160° F. 
or above, it assumes a distinctly cooked taste, which makes it 
disagreeable as a food for many people. On this account, milk 
for city supply in America is not generally heated above 145° F. 
In practically all cities where milk is consumed directly, it is 
subjected to low temperature pasteurization (145° F-) and held 
at this temperature for twenty to thirty minutes. Under this 
system the disadvantages of high pasteurization are overcome. 

For butter-m.aking purposes there are no objections to pas- 
teurizing cream at a high temperature. The common practice 



EFFECT OF HIGH HEATING ON PROPERTIES OF MILK 41 

in most of our up-to-date creameries to-day is to pasteurize 
the cream^, under the vat or holding system, to 170° F. or above, 
or, under the flash system, to at least 180° F. 

The reason why this cooked flavor is found in milk when 
heated is not well understood. It is supposed to be due to 
the effect which heat has upon the nitrogeneous constituents 
and the sugar. 

5. Precipitates Albuminoid and Ash Constituerits. — When 
milk is heated, there is a tendency for the soluble salts and a 
portion of the albuminoids to be thrown down, or changed into 
an insoluble form. 

The higher the milk is heated, the greater is this tendency. 
If a sample of milk in a flask is subjected to intense heat, and 
then allowed to stand, a fine white sediment will be deposited on 
the bottom. This is believed to consist of minerals precipitated 
from the milk. 

When milk has been heated to about 170° F., and cooled, 
rennet is unable to precipitate the curd in a normal way. The 
curd resulting from adding rennet to pasteurized milk is flocculent 
in nature. It does not assume that smooth and even texture 
that curd from raw milk has when precipitated with rennet. 
The behavior of pasteurized milk towards rennet can be ren- 
dered normal by adding a small quantity of calcium chloride 
(CaCl). Whether this would affect the quality of cheese mate- 
rially has not yet been determined definitely. According to G. 
Fascetti,^ if pasteurized milk is used for cheese-making, the 
cheese ripens more slowly than when made from raw milk. The 
same investigator also claims that a larger quantity of cheese 
is obtained per 100 parts of milk when pasteurized milk is 
used. 

6. Destroys Properties of Enzymes. — As was mentioned in 
the chapter on the composition of milk, there is a substance nor- 
mal to milk named galactase. This is an enz3mie. By heating 
milk to about 175° F. the properties of the enzyme are destroyed. 
Owing to this it is easy to determine whether a certain sample of 
milk has been pasteurized or not. Galactase is present in milk in 

^ Exp. Sta. Record, Vol. 15, No. 10, 1904. 



42 PROPERTIES OF MILK 

SO small a quantity that it cannot be determined quantitatively, 
but only qualitatively. 

A very sensitive and reliable test for determination of the 
efficiency of pasteurization was invented by Storch a number 
of years ago. This is fully described in Chapter XV on 
" Pasteurization." 

7. Divides the Clusters of Fat-globules. — The fat-globules in 
normal milk are grouped in minute clusters. When milk is 
heated, these clusters break up, and each globule exists more or 
less independently. When heated to an excessively high tem- 
perature, and exposed to this temperature very long, the fat- 
globules tend to run together. This can be proved by heating 
milk in an open vat for about half an hour. A small amount of 
yellow fat will then be seen floating on the top. 

8. Caramelizes the Sugar. — The brownish color which the 
milk assumes when it is heated excessively is due to a change which 
the milk-sugar undergoes. Fleischmann claims that the sugar 
begins to change into a substance known as lacto-caramel at a 
temperature of 160° F. This change, however, is not pro- 
nounced enough to be apparent in the color, unless the milk 
is heated a long time. The higher the temperature is, and the 
longer the milk is exposed to the heat, the more pronounced is 
the change. 

General Remarks. — While all of the above changes have 
been found by investigators to take place when milk is heated, 
they can, in a measure, be avoided, if special precautions are 
taken in the heating and cooHng with the special, recently 
improved forms of apparatus for these purposes. 

The present common practice of heating milk, for consump- 
tion as such, to 145° F., and holding at this temperature for 
twenty to thirty minutes, is accompKshed without materially 
changing its chemical or physical properties, or imparting to it a 
flavor that is at all objectionable. 



CHAPTER IV 
MILK AND ITS PRODUCTS AS FOODS 

HIGH VALUE OF MILK-FAT 

There are two methods for the classification of foodstuffs for 
animals and man, and both of these will be briefly considered in 
this chapter, with special reference to milk and its constituents — 
particularly milk-fat — as not only valuable but indispensable 
parts of the dietary. 

The older method may be spoken of as the chemical method. 
It considers and classifies foods largely in accordance with their 
content of water, protein, carbohydrates, fats and mineral matter. 
This, in itself, is quite incomplete, as will be shown later. 

The newer method, which is known as the biological method, 
is based upon a study of the properties and values of the different 
foodstuffs, through feeding them and noting their effect upon 
growth, health and reproduction . This method, though compara- 
tively new, has made very rapid strides, and has established the 
fact that food constituents which come under the same chemical 
head are by no means either alike or of equal nutritive value. 

There is neither the hope nor the expectation that the bio- 
logical will supersede the chemical classification of foods and 
foodstuffs, in the sense of dispensing with the aid of chemistry. 
The true, unbiased student of the problems of nutrition recognizes 
two things; first, that the chemical method has rendered and 
will continue to render a very large service, and, second, that in 
itself it is too mechanical and incomplete. 

In the last analysis, the biological classification of foodstuffs 
must prevail, but this does not mean that it and chemistry are 
at variance with each other. Rather it means that there must 
be a merging of the chemical into the larger or biological method, 
and that in future a larger, fuller, more intelligent and less 

43 



44 MILK AND ITS PRODUCTS AS FOODS 

mechanical use will be made of chemistry as an aid in deter- 
mining the values of the different foodstuffs and how they may 
best be combined with each other in the compounding of more 
economical and complete rations and diets on which animals and 
man will grow and thrive. At times the biological study of food- 
stuffs may move in advance of chemistry, as it has already done 
in discovering the presence in milk-fat of a fat-like or fat-soluble 
substance, as yet unidentified, which renders this fat al'together 
superior to other animal and vegetable fats lacking this growth 
and health -promo ting foodstuff. It is the province of chemistry 
to ascertain, if possible, what this substance is. The same may 
be said of a water-soluble substance which is not nearly so limited 
as to its sources, being present in sufficient quantity in cereal 
grains and most of the mixed diets. 

CHEMICAL CLASSIFICATION OF MILK AND ITS PRODUCTS 

AS FOODS 

From the chemical standpoint, the constituents of the food 
material consumed by animals and man are classified under the 
heads of water, combustible matter and ash, mineral matter or 
salts — all three terms being applied to the last class. 

The combustible matter includes the carbohydrates (such as 
starches and sugars), the fats (such as milk-fat, olive oil and 
other plant oils, and meat-fat), and the proteins (such as the curd 
of milk, the gluten of wheat and the muscle fiber of lean meat). 

The carbohydrates and fats are largely burned to supply 
heat and energy, and are also used for the making of fat in the 
body and in milk. 

The proteins are used, in part, for the same purposes as the 
carbohydrates and fats, but their distinct function, which these 
latter cannot perform, is that of supplying material for the 
making of muscle and other body tissue, and the protein of milk. 

The ash or mineral matter is used for making bone, regulating 
the heart action and the elasticity of the muscles in general, and 
preventing acidity of the blood and tissues. 

Under the older classification of foods we find that milk 



BIOLOGICAL CLASSIFICATION OF FOOD 45 

and Its products are given a very high place, on account of their 
high content of the different foodstuffs or constituents, and their 
high degree of digestibihty. A quart of average milk is consid- 
ered by such high authorities as Sherman of Colmnbia University 
to be approximately equal in food value to a pound of steak, 
or eight or nine eggs. He is here referring chiefly to their heat 
and energy value and high degree of digestibility. 

American cheese (a Cheddar cheese) may be regarded, in a 
very large sense, as a concentrated form of milk, as it contains 
most of the milk constituents, excepting the sugar. It has about 
twice the food value of average meat. On this point Sherman 
says " Generally speaking, cheese sells at no higher price than 
the ordinary cuts of meat. It is a fair general estimate that a 
given amount of money spent for American cheese will buy about 
twice as much food value as it would if spent for meat." 

Altogether apart from a distinctive and most important 
function which will be considered later, butter has a very high 
heat and energy value — a pound being equal to about five 
quarts of average milk. It is by no means merely a rehsh, as it 
has in the past been considered by many. 

We cannot here afford the space to discuss the food values of 
the various other milk products, such as cream, ice-cream and 
condensed milk. It will suffice to say that cream occupies an 
intermediate position between milk and butter, combining the 
features of both. 

BIOLOGICAL CLASSIFICATION OF FOODS 

The High Value of Milk and Milk-fat under this Classification 

The biological study of foods — based upon observations as to 
the influence of various foodstuffs upon the growth and thrift of 
animals — ^has revolutionized our ideas with regard to problems 
of nutrition, and has estabhshed the fact that the biological 
classification of foods is the true one. In doing so it has shown 
that milk and milk-fat have values as foods which, a few years 
ago, were quite unknown, and which as yet have not been deter- 
mined chemically — or at least have been determined only in part. 



46 MUX AND ITS PRODUCTS AS FOODS 

It was but natural that biological students of the problems 
of nutrition should give their attention to milk and endeavor to 
ascertain wherein its different constituents excelled the corre- 
sponding constituents of other foods. Knowing that the young 
grow and thrive on a diet composed exclusively of milk, they 
realized that this food must contain nutritive material of an 
exceptionally high order. 

Proteins 

The proteins of plants differ from those of animals and of each 
other. Anim_als do not take the proteins of their foods, whether 
of plant or animal origin, and use them as such, without any 
change. In the processes of digestion and assimilation, animals 
break proteins up into the simpler substances, amino-acids, and 
from these build up the proteins of the muscle and other tissues 
of the body. 

There are eighteen amino-acids that are considered in nutri- 
tion problems. The protein of wheat (gluten) is able to supply 
only a limited number of these in sufficient quantity, and some 
not at all. The proteins of the corn kernel (zein, etc.) are 
able to supply others, and so on with the proteins of the different 
foods; but none of these is a complete protein food for the animal 
body. The chief protein of milk (casein) is, however, an excep- 
tion, being a very complete and well-balanced protein, which is 
able to supply the different amino-acids in sufffcient quantities 
and right proportions to build up muscle and other protein 
tissue of the body. Thus we would say that milk furnishes pro- 
tein of a quality quite superior to that of almost any other food. 
This we see exemplified in the fact that the young animal lives, 
grows and thrives on milk alone. 

Ash or Mineral Matter 

In the ash or mineral matter of the food there must be a 
sufficiency of such elements as sodium, potassium, calcium, 
magnesium, iron, etc., in the form of inorganic salts. These 
perform very important functions. Each has its work to do, 
and they are not inter chans^eable. 



BIOLOGICAL CLASSIFICATION OF FOODS 47 

In a mixed diet, there is usually, but not always, a sufficiency 
of the compounds of the different elements mentioned. We 
quote Sherman upon this point: " There must also be main- 
tained in the body a proper balance between sodium and calciimi 
(the metal of lime). For example, the rhythmical contraction 
and relaxation of heart muscle, which constitutes the normal 
beating of the heart, is dependent upon this muscle being bathed 
by a fluid containing the proper concentration and quantitative 
proportions of sodium and calcium. Calcium is not always suf- 
ficiently abundant even when the food is freely chosen; hence the 
richness of a food in calcium is a factor affecting its value. "^ 
McCollum and Simmonds found as a result of their experiments, 
" that the deficiency in mineral elements in wheat and other seeds 
is Hmited to three elements, calcium, sodium and chlorine. "^ 

The ash of milk is present in hberal quantity, is of high qual- 
ity and well balanced, and is rich in its lime content as a source 
of calcium. There is more lime in a pint of milk than in a pint of 
limewater. 

Two Unidentified hut Essential Food Substances — One of These 
in Milk-fat hut not in Ordinary Fats 

There are, in association with some of the foodstuffs, sub- 
stances which have not as yet been identified chemically, pos- 
sibly on account of the minute quantities in which they are 
present; and yet observation, in feeding experiments, has shown 
that they are indispensable. If these are absent from their 
foods, animals will neither grow nor retain vigor. 

As early as 1906, Hopkins of Cambridge (England) showed 
conclusively that on an apparently complete food made up of 
purified proteins, ordinary fats, carbohydrates and salts young 
rats would not grow, but that when a very small amount of milk 
was used — enough to make up about 4 per cent of the dry matter 
of the food — growth became entirely satisfactory. This led him 
to conclude that there were present in milk unidentified food 
substances which he termed " accessory " articles of the diet. 

' Food Products, pp. 19 and 20. 

2. The Newer Knowledge of Nutrition, p. 23. 



48 MILK AND ITS PRODUCTS AS FOODS 

These would be what McCollum terms the " fat-soluble A," 
which is found in milk -fat but not to any appreciable extent in 
the ordinary fats, and the " water-soluble B," which is more 
generally distributed in foods, particularly in diets of mixed 
foods. 

Bloch, a Danish physician, observed about forty cases of 
severe eye trouble, accompanied by ulceration, in children near 
Copenhagen. * This would, without doubt, have ended in blind- 
ness. These children had been receiving skim-milk, instead of 
whole milk, in their diet, and were practically deprived of milk- 
fat in their food. When the younger of them were given mother's 
milk., and the older either cow's milk or cod liver oil, they 
responded and recovered. He attributed the trouble to the lack 
of fat in their foods; but it will be noted that in all cases the real 
cause of recovery was the feeding of fats containing the, as yet, 
unidentified fat-soluble which is present in the fats of milk, the 
yolk of egg, the liver and other body glands, and the leaves of 
plants, particularly such plants as alfalfa and the clovers. 

Mori found fourteen hundred cases of similar eye trouble 
amongst children in Japan; these responded to the feeding of 
chicken livers. 

It has been found both by McCollum and Davis, and by 
Osborne and Mendel that milk-fat contains a fat-like or fat- 
soluble substance whose presence or absence in a food, otherwise 
entirely satisfactory, means the difference between growth and 
no growth in the young. In addition to this, both these pairs of 
investigators found that, deprived of such a fat as milk-fat, the 
young animal would develop a disease of the eyes which would 
ultimately cause bhndness and, if persisted in, would end in 
death; but that if this fat were restored in time the eyes would 
become normal again and the young animal would return to its 
former health and vigor and resume normal growth. 

It would be unfair to credit any one man, or set of men 
collaborating with each other, with the discoveries that have 
been made during the past fifteen or twenty years — and par- 
ticularly within more recent years — through the biological study 
of foods. The list of investigators is rather a formidable one. 



BIOLOGICAL CLASSIFICATION OF FOODS 49 

and, as has already been indicated, includes students of the sub- 
ject extending from America to Europe and even to far-away 
Japan. Without doubt the best known of these in America is 
Dr. E. V. McCollum, whose extensive and most valuable articles 
appeared in Hoard's Dairyman and other farm and scientific 
journals, and who has issued a valuable book on the subject, 
entitled, " The Newer Knowledge of Nutrition." In this book 
he outHnes the investigations conducted by him and his co- 
workers — Babcock, Hart, Davis, Steinbeck, Humphrey, Parsons, 
Funk, Kennedy, Simmonds and Pitz — and also familiarizes us 
with the work of many other investigators. 

As McCollum intimates, in order to secure reliable and exact 
data it was necessary to feed purified foodstuffs (purified protein, 
carbohydrates, fats and mineral salts), and in order to do this 
and secure sufficient data within a reasonable time it was neces- 
sary to experiment with small animals. For these reasons, 
the experiments were conducted mostly with young rats, although 
like results were also obtained with other animals, including 
cattle and pigs. Accumulated data, from a variety of sources, 
show that the results secured are equally applicable to the diferent 
animals, including man. 

In one of the earHer experiments with rats, conducted by 
McCollum and Davis, they fed a diet composed of purified pro- 
tein (casein) to the extent of i8 per cent, lactose or milk-sugar 
20 per cent (supposed to be pure), about 5 per cent of some fat, 
together with a salt mixture made up in imitation of the mineral 
matter of milk, and the balance of starch to make up 100 per cent. 
The results of this experiment were that when the fat used was 
milk-fat growth could be secured, but that when this was 
replaced by such fats as lard, olive oil or other vegetable oils, 
there was no growth. When the fat of yolk of egg was used 
instead of milk-fat it also induced growth. These experiments 
established the fact that fats from different sources are by no 
means equal in dietary value. 

Following this a more elaborate experiment was planned and 
carried out by McCollum and Davis. It will be noted that the 
diet of purified foodstuffs, which proved a satisfactory one, was 



50 MILK AND ITS PRODUCTS AS FOODS 

made up of purified milk constituents. McCollum and Davis 
next tried the wheat seed or kernel. They reasoned that it con- 
tained protein, carbohydrates and mineral salts and fats or oil, 
and that if these were mostly equal in quahty to those of milk 
the only foodstuff that might have to be added would be a growth- 
promoting fat. They first fed wheat alone and then tried the 
improvement of it with respect to one dietary factor at a time. 
The following indicates the different combinations in which 
wheat was fed, with results secured: 

(i) Wheat alone No growth, short life. 

(2) Wheat, plus purified protein No growth, short life. 

(3) Wheat plus a salt mixture which gave it a 

mineral content, similar to that of milk. Very little growth 

(4) Wheat plus a growth-promoting fat (milk- 

fat) No growth. 

(s) Wheat, plus the protein, plus the salt mix- 
ture. Good growth for a time, few or no 

young, short life. 

(6) Wheat, plus protein, plus a growth-pro- 

moting fat (milk-fat) No growth, short life. 

(7) Wheat, plus the salt mixture, plus the 

growth-promoting fat (milk-fat) Fair growth for a time, few or no 

young, short life. 

(8) Wheat, plus protein, plus the salt mixture, 

plus a growth-promoting fat (milk-fat) Good growth, normal number of 

young, good success in rearing 
young; life approximately the 
normal span. 

This series of experiments again proves the necessity of a 
growth-promoting fat. But it does more than this; it shows that 
the proteins and mineral matter from different sources are not 
of equal value, those of milk being altogether superior in this 
respect to those of such a food as wheat. Other experiments 
proved that the seeds of other cereals are, like wheat, quite 
incomplete in themselves as diets. 

In following up this investigation it was found that when 
polished rice was substituted for wheat, in No. 8 of the series of 
experiments just outlined, the diet failed utterly to induce 
growth. This was puzzling. The investigators had been able 
to induce successful growth through feeding a diet composed of 



BIOLOGICAL CLASSIFICATION OF FOODS 51 

purified protein (casein), milk-sugar (supposedly pure), salts in 
imitation of the mineral matter of milk, and milk-fat. They 
could see no reason why the polished rice, supplemented by puri- 
fied protein, suitable salts and milk-fat should not be a complete 
food. This was cleared up subsequently by establishing the 
fact that the milk-sugar used in the former of these two experi- 
ments, and the germ or chit of the cereal seeds, which had been 
rubbed off the rice, contain a water-soluble substance essential for 
growth, health and vigor. 

The conclusions finally reached were, first, that amongst 
the food substances (protein, carbohydrates and ash or mineral 
matter) coming from different sources there is a marked differ- 
ence in quahty, and that those from milk are of a very high order; 
and second, that there are two as yet unidentified substances 
which are indispensable to growth and health, namely, the 
unknown substance which is present in milk-fat, the fat of yolk of 
egg and some of the glandular fats, which McCollum and Ken- 
nedy subsequently designated " fat-soluble A," and a second 
substance soluble in water, which they designated " water- 
soluble B." The absence of the former (fat-soluble A) not only 
prevents growth, but also causes a serious eye trouble which, if 
not corrected in time, will end in blindness and death. We have 
already illustrated this point. The absence of the water- 
soluble also prevents growth, and causes serious physiological 
disturbances resulting in a form of paralysis, beri-beri, which is 
quite prevalent where such foods as polished rice and bolted 
flour form the main article of diet. 

But this water-soluble is present in most ordinary food 
substances, and particularly in a mixed diet, whereas the sources 
of the fat-soluble are quite limited, the fat of milk, in the form 
of milk and butter, being the chief of these. 

In support of what has been said, the utterances of some of 
our leading physiologists and students of nutrition may be 
quoted. 

Dr. H. C. Sherman, Professor of Food Chemistry, Columbia 
University: " Especially in the feeding of children should milk 
be used freely, because of its many advantages as a tissue- 



52 MILK AND ITS I'RODUCTS AS FOODS 

building and growth-promoting food. A quart of milk a day 
for every child is a good rule easy to remember." 

United States Food Administration: '' Milk is one of the most 
important food sources the human race possesses. For the 
proper nourishment of the child it is absolutely indispensable 
and its use should be kept up in the diet as long as possible. Not 
only does it contain all the essential food elements in the most 
available form for ready digestion, but the recent scientific dis- 
coveries show it to be especially rich in certain peculiar properties 
that alone render growth possible. This essential quahty makes 
it also of special value in the sick room. In hospitals it has also 
been shown that the wounded recover more rapidly when they 
have milk. 

" For the purpose of stimulating growth, and especially in 
children, butter-fat and other constituents of milk have no 
substitutes." 

Dr. E. V. McCollum, Johns Hopkins University: " I have 
come to the conclusion, after carefully analyzing the probable 
effectiveness of the combinations of foods employed in human 
nutrition, that the efficiency of a people can be predicted with 
a fair degree of accuracy from a knowledge of the degree to which 
they consume dairy products. Probably the use of meat and of 
milk and its products will, in nearly all cases, run more or less 
nearly parallel, and I venture to assert that it is the milk and 
butter and cheese, and not the meat which has the good influence 
in the promotion of the virile qualities of the people. 

" Milk is worth much more than its energy value or than its 
protein content would indicate. It is the great factor of safety 
in making up the deficiencies of the grains which form and must 
continue to form the principal source of energy in our diet. 

" It seems probable that the only unidentified substance 
which is physiologically indispensable, which is not sufficiently 
abundant in the diets employed by the people of the United 
States and Europe where there are used insufficient amounts of 
milk, butter, cream, eggs and the leafy vegetables, is the fat- 
soluble A." 

" I wish to again emphasize the fact that there is no way to 



BIOLOGICAL CLASSIFICATION OF FOODS 53 

supply this dietary factor (fat-soluble A) in the food of children 
except in the form of milk-fat, and milk is therefore an indis- 
pensable food for the young." 

Attention should be called to one other point. It has been 
suggested by some that possibly pasteurization of milk or cream 
destroys the growth-promoting qualities of the " fat-soluble A " 
in the fat. Osbourne and Mendel found that passing live steam 
through milk-fat for two hours did not affect it, and McCollum 
and Davis found that it was not affected by being heated to 
the boiling-point of water. This should be satisfactory evidence 
that pasteurization of milk or cream in no way affects the growth- 
promoting quahties of the milk-fat. 



CHAPTER V 
FERMENTS IN MILK 

Definition. — The changes which milk undergoes when 
allowed to stand at a suitable temperature are commonly called 
fermentations, and the agencies which bring about these changes 
are called ferments. At one time the ferments were classified 
under two heads, viz., organized ferments (bacteria, yeasts 
and molds) , and enzymes or unorganized ferments, such as those 
found in rennet and other fluids in the digestive tracts of animals. 
This distinction is no longer made, since bacteriologists and 
physiological chemists have reached the conclusion that the 
fermentative changes, due to the action of germ life, are caused 
by enz5rmes which these micro-organisms produce. However, 
the enzymes themselves may, from a dairy standpoint, be classi- 
fied as follows : 

(i) The pre-existing enzymes of milk, or those which are 
formed during milk secretion and consequently are in the milk 
when it is drawn from the cow. The first of these was dis- 
covered by Babcock and Russell of the Wisconsin Station, in 
1889, and was named galactase by the discoverers. It is a 
tryptic ferment. Since then others, such as catalase and peroxi- 
dase, have been discovered. It would seem, from investigations 
made by Russell and Babcock, that the inherent enzymes of 
milk, which are digesting ferments, are essential to and play an 
important role in the ripening of the Cheddar type of cheese. 
They find that it is impossible to produce a typical, normal 
Cheddar cheese from thoroughly pasteurized milk. According 
to Storch, the peroxidase has the power of decomposing hydrogen 
peroxide and setting free " active " oxygen. As this ferment is 
not destroyed until milk or cream is heated to a high temperature, 

64 



FAVORABLE CONDITIONS FOR BACTERIAL GROWTH C:, 

it forms the basis for the Storch test for the efficiency of the pas- 
teurization of milk or cream for butter-making. This test is 
described in the chapter on Pasteurization. 

(2) Enzymes developed through the action of germ life — 
bacteria, yeasts and molds. These are many and varied, and 
cause most of the changes that take place in milk and its products, 
such, for example, as the ordinary souring of milk or cream, and 
the development of flavor and aroma in cream ripening. 

(3) Enzymes found in the digestive fluids of animals. All are 
familiar with the fact that rennet is used in cheese-making. It 
contains a ferment known as rennin. 

It is the second class of ferments or enzymes, the class due to 
the action of germ life (principally bacteria) , which is of the great- 
est importance in connection with dairying, and with the control 
of which the dairyman concerns himself most. These ferments 
are capable of working profound changes, some desirable and some 
very undesirable. 

Size and Shape of Bacteria. — In size, bacteria are the smallest 
organisms that exist, so far as known. The size varies consider- 
ably. Russell 1 gives the average diameter as 30000 of an inch. 
They are so inconceivably small and light that nine hundred 
bilhons of them would only weigh ^t of an ounce. ^ 

Bacteria also vary considerably in shape. They are as a 
rule classed into three groups: (i) The bacillus or rod-shaped; 
(2) The coccus or ball-shaped; (3) The spirillum or spiral-shaped 
(Hke a corkscrew) . Some types of bacteria are classified accord- 
ing to the way in which they adhere to each other. For instance, 
when two cocci occur together and form a pair, they are called 
diplococci; when cocci occur in chains, they are called strepto- 
cocci; when cocci appear in bunches, they are called staphylo- 
cocci, etc. 

FAVORABLE CONDITIONS FOR BACTERIAL GROWTH 

Food. — Bacteria, like other plants, need food for their exist- 
ence. The food passes into the bacterial cell in solution, but 
many organisms use materials not in solution by producing 

^ Dairy Bacteriology. ^ Milk, Its Nature and Composition, by Aikman. 



56 FERMENTS IN MILK 

enzjrmes that dissolve them. Nitrogen, carbon, oxygen, hydro- 
gen and mineral matter are essentials for bacteria. These sub- 
stances are furnished in abundance in milk from casein, albumen, 
milk-sugar, and the mineral salts. Butter-fat in milk is said to be 
of little value as a food for bacteria. 

Some organisms, including yeasts and molds, tolerate con- 
siderable amounts of acid, while others do not. Most bacteria, 
however, prefer a neutral or slightly alkaline substance. Dark- 
ness is essential to som.e bacteria, and is preferred by the majority 
of the different species. Bright sunlight is a very effective 

^ ml - ^ / 5 M V, s I ^ ,1 ,>i 

Fig. 7. — a, single bacterium; b, progeny resulting from the growth of a bacterium 
during 24 hours in milk at 50° F.; c, progeny of a bacterium during 24 hours 
growth in milk at 70° F. At 50° F. multiplication v/as 5-fold. At 70° F. 
the multiplication was 750-fold. (Bui. 26, Storrs, Conn.) 

germicide; it is fatal to all species, so far as known. Some germs 
require air for their growth. These are called aerobic. Others 
again grow only in the absence of air. These are called anaerobic. 
Some grow under either or both conditions, and are called 
facultative. 

Temperature. — Favorable temperature is essential to bac- 
terial growth. Temperature is, indeed, the most important 
means by which the growth and development of bacteria can be 
controlled. The range of temperature at which bacterial 
growth is hkely to occur may be placed between freezing-point and 
a little above 110° F. There are, however, exceptions to this 



FAVORABLE CONDITIONS FOR BACTERIAL GROWTH 



57 



range. Some few species will grow at as high a temperature as 
140° F., and B. hulgaricus will grow very rapidly at 110° F. 

The growth of bacteria at these extreme temperatures is 
usuall}'^ very slight. Even at 50° F. the rate of growth is very 
slow. According to experiments conducted by Dr. Conn, the 
multiplication of bacteria at 50° F. was 5-fold, while at 70° F. 
the multiphcation was 750-fold. The following table shows the 
number of bacteria per cubic centimeter in milk kept at different 
temperatures.^ 



No. at 
Outset 



46,000 
47,000 

50,000 



In 12 


In 12 


In 5° 


Hours 


Hours 


Hours 


at 50° 


at 70° 


at 50° 


39,000 


240,500 


1,500,000 


44,800 


360,000 


127,500 


35,000 


800,000 


160,000 



In 50 Hrs. 


No. of 


or at Time 


Hours be- 


of Curd- 


fore Curd- 


ling at 70° 


ling at 50° 


542,000,000 


190 


7Q2,000,000 


289 


36 hours 




2,560,000,000 


172 


42 hours 





No. of 
Hours be- 
fore Curd- 
ling at 70° 

56 
36 

42 



All bacteria do not have the same optimum growing tem- 
perature. Some species develop most rapidly at one tempera- 
ture, while other species prefer a different temperature for the 
greatest development. It is on this account that certain tem- 
peratures are employed in ripening starters and cream. Accord- 
ing to researches by Conn, Bacterium aerogenes develops very 
rapidly in milk at 95° F. This particular species, producing 
much gas and an unpleasant flavor, sours milk very rapidly. As 
a rule, milk which has been held at this high temperature con- 
tains a preponderance of this undesirable species of bacteria. 
At 77° F. results are more uncertain; the species of bacteria 
which will predominate in milk at this temperature depends in 
large measure upon the number of each kind originally present. 
According to Conn Streptococcus lacticus has the highest relative 
growth at about 70° F. This particular species produces no gas, 
and its presence is desirable in cream for butter-making. Milk 



1 Bull, 26 Storr's Sta., Conn. 



58 FERMENTS IN MILK 

kept at this temperature will, in most cases, providing it has pre- 
viously been properly treated, develop a pleasant acid taste, will 
curdle into a smooth uniform coagulum, and will contain a pre- 
ponderance of the species of germ mentioned above. 

At as low a temperature as 50° F. acid-producing types of 
bacteria do not develop very well. But Conn maintains that 
miscellaneous species of bacteria that produce unfavorable 
results develop at this temperature. While milk does not easily 
sour at this temperature, it should be remembered that undesir- 
able germs are constantly developing. 

As it is practically impossible to exclude all of the bacteria 
from milk during milking and the handling of the milk, it is 
very essential that the multiplication of the germs present be 
checked, or at least retarded; and this can be done by controlling 
the temperature of the milk. As low temperature is effective in 
checking the multiplication of the bacteria, the sooner the milk 
can be cooled after it is drawn, the better it will be Hkely to keep. 

Moisture. — Moisture is one of the essentials for bacterial 
growth. As milk is composed largely of water, bacteria find in 
milk a good medium for growth. All the other required food 
elements are also found in abundance in milk. Damp utensils 
and rooms are always more conducive to the growth of germs 
than are utensils and rooms which are thoroughly dried and 
ventilated. This is well illustrated by a refrigerator. A very 
damp dark refrigerator is always more conducive to the growth 
of molds in butter than is a dry refrigerator. 

Unfavorable Conditions for Bacterial Growth. — The reverse 
of the favorable conditions mentioned above would be unfavorable 
to the growth of bacteria. As it is practically impossible to make 
conditions unfavorable for the growth of bacteria by taking 
away food, other means must be used. Extremely high tem- 
peratures destroy bacteria. Low temperatures check their 
growth, but so far as known do not destroy them. Absence of 
moisture and presence of direct sunlight are conditions which are 
not conducive to bacterial growth. Certain chemical substances 
when added to milk, or to the medium in which the bacteria are 
present, are very unfavorable to their growth. Some of these 



UNFAVORABLE CONDITIONS FOR BACTERIAL GROWTH 59 

chemicals entirely destroy all germ life even when added in very 
small quantities. These are called disinfectants (formaldehyde, 
corrosive subhmate, etc.). Other chemicals are more mild in 
their effect upon germ growth, and merely inhibit or retard the 
growth of micro-organisms. The chemicals which have this 
milder effect upon germs are called antiseptics. Boracic and 
salicylic acids are examples. Practically all disinfectants are 




Fig. 8. — Shows a plate exposed in pasture where air must have been very pure 
and free from germs. (Bui. 87, Nebraska.) 

violent poisons, and should not be used in any quantity or in 
any form in milk or dairy products which are intended for human 
food. The milder preservatives or the antiseptics, are, as a rule, 
not so poisonous or injurious to human health. In some coun- 
tries they are allowed to a small extent. For instance, according 
to reports, the laws of England permit the use of boracic acid 
in butter to the extent of 0.5 of i per cent. It is, however, safest 
not to use any of these chemicals, except for preserving samples 



60 



FERMENTS IN MILK 



for analytical or similar purposes. As low and high tempera- 
tures are so effective in producing unfavorable conditions, these 
should be chiefly employed in controlling the growth of micro- 
organisms in the dairy industry. 

Kind of Germs Found in Milk. — The number of species of 
germs found in milk has not yet been definitely established, due 
chiefly to the fact that it is in some instances difficult for bacteri- 
ologists to differentiate one species from another. The descrip- 




~-™».i!ff,(.jv^,-^^taft*^».j«;%-'S'.?^fi>x';-^«m' 





Fig. g. — Shows a plate exposed one-half minute under a cow's udder treated with a 
5 per cent solution of carbolic acid. (Bui. 87, Nebraska.) 

tion of one species of bacteria by two different bacteriologists 
may vary considerably, as the characteristics of the germs 
depend so much upon the conditions prevaihng throughout the 
classification process. Over 200 different species have been 
described. It is possible, however, though all of these types 
may have different morphological and physiological character- 
istics as described by different bacteriologists, that some two or 
more of the 200 types may belong to one species. 



KIND OF GERMS FOUND IN MILK 



61 



For this purpose, it is sufficient to classify the bacteria into 
three groups, viz., (i) those which are harmful to the butter- 
making industry, (2) those which are beneficial, and (3) those 
which are indifferent, or produce neither good nor bad results. 

From the farmer's or milk-producer's standpoint, none of 
these bacteria are desirable. Each milk-producer should make 
it a point to prevent their entrance and suppress their develop- 




FiG. 10. — Shows plate exposed one-half minute under cow's udder treated by merely 
brushing with the hand; each little spot represents a colony of some kind of 
bacteria. (Bui. 87, Nebraska.) 

ment in milk and cream to as great an extent as possible. The 
creamery operator should endeavor to suppress all of the harmful 
germs, and foster the development of the desirable ones. 

The germs which are desirable belong to the acid-producing 
types, such as Streptococcus lacticus, and the associated flavor 
and aroma-producing types, such as Streptococcus citrovorus. 

The harmful bacteria include those which produce bitter 
milk, red milk, blue milk, yellow milk, slimy milk, gas, and 



62 FERMENTS IN MILK 

undesirable flavors and aromas. There are a number of species 
belonging to this group. The pathogenic germs, or disease- 
producing bacteria, must also be classed with the harmful bac- 
teria. It is not the intention in this work to give an extended 
discussion of this subject. For such discussion see special works 
on Dairy Bacteriology. 

Number of Bacteria in Milk. — The number of bacteria found 
in milk varies so much that it is practically impossible to state 
accurately the average number. The number of germs found 
varies according to several conditions, such as degree of cleanli- 
ness of cows, utensils, and milker; degree of purity of the atmos- 
phere when the cows are milked; the temperature at which the 
milk is kept and the time it is held. When the milk is being 
produced under the best practical sanitary conditions, the number 
of germs need not exceed 10,000 per cubic centimeter. Such 
results cannot be obtained unless extreme precautions are taken. 
Milk produced under average farm conditions seldom contains 
less than 50,000 germs per cubic centimeter shortly after the 
milking. Milk which is produced under filthy conditions, and 
which is several hours old, may contain several millions of bac- 
teria per cubic centimeter. 

Sources of Bacteria in Milk. — Bacteria are widely distributed 
in nature. They float in the atmosphere and adhere to particles 
of dust. Especially is this so in the dusty cow-stable. They 
are present in all well water to a greater or less extent, and are 
very abundant in streams and rivers. They are present in the 
soil to a depth of several feet, the number decreasing with the 
depth. As these germs are practically present everywhere, the 
sources of germs in milk may be said to be all around us. The 
principal sources of germs in milk are, however, unclean dairy 
utensils, unclean cows, and unclean surroundings. As these 
germs multiply chiefly by fission, or by one cell dividing into two, 
it is plain that the number of germs will increase very rapidly 
under favorable conditions. Under the most favorable condi- 
tions it requires approximately twenty minutes for this process of 
fission to take place. 

Some germs develop small bodies within the cell, called 



SOURCES OF BACTERIA IN MILK 63 

spores. It is not difficult to destroy the sporeless cell by heat, 
but the spores are very resistant to unfavorable conditions. 
The spore-bearing bacteria are difficult to kill ; boiling for a short 
time will not destroy them. Hammer is satisfied that they are 
destroyed by prolonged boihng. Another method is to heat the 
milk to destroy all the organisms in the vegetative stage, then 
cool it to a temperature favorable to growth and allow the spores 
to develop into the vegetative stage, and again apply heat. In 
this way milk can be rendered entirely sterile. A single heating 





Fig. II. — The wrong and the right kind of a milk-pail. A, the ordinary type of 
pail showing sharp angle between sides and bottom; B, the same properly 
flushed with solder so as to facilitate thorough cleaning. The lower figure 
represents a joint as ordinarily made in tinware. The depression a affords 
a place of refuge for bacteria from which they are not readily dislodged. This 
open joint should be filled completely with solder. (From Bui. 62, Wis.) 

under pressure (fifteen minutes at 1 5 pounds pressure) kills them 
at once. 

It has been demonstrated by several investigators that freshly 
drawn milk is not a good medium for bacteria to develop in. 
In fact, several experiments seem to indicate that milk acts as a 
germicide to certain varieties of bacteria. For instance, the 
cholera germ is to some extent destroyed in fresh milk, but it is not 
known to what extent. Organisms producing lactic acid check 
the multiplications of these pathogenic bacteria. This germicidal 
property is said to be more or less common to all the animal 
secretions. 



64 FERMENTS IN MILK 

Effect of Thunder-storms on Souring of Milk. — It is a common 
impression that thunder-storms hasten the souring of milk. This 
was attributed to the electricity in the air accompanying the 
storm. Experiments b)^ several investigators have proved 
that electricity does not have any effect on hastening the fer- 
inentative changes of milk. The reason why milk sours more 
quickly when an electrical storm is approaching is that the air 
temperature is usually higher then than at any other time. This 
higher temperature warms the milk and creates more favorable 
conditions for the rapid multiplication of the germs present in the 
milk. It is for this reason that milk sours more quickly during or 
previous to a thunder storm than at any other time. 



CHAPTER VI 
ABNORMAL MILK 

Colostrum Milk. — Colostrum is the milk yielded immediately 
after calving. As the time of calving approaches, a cow usually 
diminishes in her milk-producing capacity. Most cows become 
dry about two months previous to parturition. If they do not 
naturally stop giving milk, they should be dried up so as to have 
a seven weeks' rest before calving. When the rest has been 
given, the cows yield, immediately after calving, milk which has 
a composition and characteristics different from those of normal 
milk. If the cow continues to give a copious flow of milk up to 
the time of calving and is not allowed any rest, the difference in 
the milk yielded before calving and after calving is comparatively 
slight. 

The composition of colostrum varies considerably during the 

first three days after calving. According to Engling, as reported 

by Richmond, the composition is as follows: 

Per Cent 

Water 71.69 

Fat 3.37 

.„ . ., (Casein 4-83 

Albummoids 1 , „ 

[ Albumen 1 5 • ^5 

Sugar 2 . 48 

Ash 1 . 78 

Colostrum greatly changes in composition and appearance as it 
gradually assumes the characteristics of normal inilk. It is at 
first reddish yellow in color, and has a viscous and slimy con- 
sistency. It is a food which the newly born calf should not be 
deprived of, as it seems to be specially suited for the digestive 
tract of the young calf. 

65 



66 ABNORMAL MILK 

It will be seen from the above table that the water content 
of colostrum is less than that of normal milk. The fat content 
is also a Httle lower. The most striking characteristics of colos- 
trum, however, are the low content of sugar, and the large amount 
of albumen. Of the latter substance very little is present in 
normal milk. The mineral constituents of colostrum also run 
quite high. Its specific gravity varies from 1.046 to 1.079. 
When it is boiled, the nitrogenous matter coagulates. The 
colostrum is not considered suitable for food until about four 
days after parturition. Whenever it can be boiled without coag- 
ulating, it is claimed to be safe to use. At times a cow's udder 
becomes inflamed after calving. In such cases the abnormal 
qualities of the cow's milk will extend over a greater period of 
time than that mentioned above. 

Salty Milk. — The average chemical analysis of salty milk as 
calculated from results obtained by the analysis of such milk 
from four cows, given by Boggild,^ is as follows: 

Water 91 . 09 

Fat 2 . 09 

Nitrogenous matter 2 . 90 

Sugar 3.01 

Ash 85 

It has an average specific gravity of 1.0244. 

Salty milk does not occur very often, but whenever it does 
occur, it is difficult, and, so far as known, impossible to cure 
without drying up the cow. Two samples of such milk have 
recently come within the authors' notice. It had the appearance 
of normal milk, a foul smell, and a very salty taste. The two 
samples contained 1.7 per cent and 1.9 per cent of fat respectively. 
They soured and curdled in a normal way at living-room tem- 
perature in about thirty hours. At this stage they were very 
foul in smell, and unpleasant in taste. 

The cows which had produced this milk had both calved 
about three months previously. It occurred in the month of 
July, when pastures were quite good. The udders of the cows 

^ Maelkeribruget in Denmark. 



BLOODY OR RED MILK 67 

were in an apparently normal condition. At first it was thought 
that some conditions in the pasture caused this abnormal milk. 
The cows were taken into the barn, and fed on dry food for 
two weeks, but without any change in the quality of the milk. 
Gradually they dried up. 

The secretion of this salty milk was believed to be due to the 
long time during which the cows had been yielding milk without 
any rest. They had been given no rest previous to the last 
calving. It is also believed that this quality of milk will occur 
more frequently when the cows are near the close of the lactation 
period . 

While the above two causes are perhaps the most common, 
they are not the only ones. Salty milk has been obtained in 
cases where these reasons could not be ascribed. Boggild has 
found that salty milk has been secreted by cows with abnormal 
udders. He has also demonstrated that it was the diseased part 
of the udder from which the salty milk was yielded. The healthy 
portion of the udder yielded normal milk. It is possible that 
an obscure, diseased condition of the udder may be the entire 
cause. 

Salty milk is of course undesirable in the dairy or creamery. 
It is very disagreeable to the taste, and in a fermented stage 
becomes very foul. 

Bloody or Red Milk. — Bloody, or red milk is caused, first, 
by an abnormal condition of the cow's udder, which may or may 
not be apparent; and second, a red color may be developed in 
milk after standing, through the action of bacteria. 

The bloody milk, caused by an inflamed udder, often assumes 
a reddish-yellow appearance, and may, if not examined care- 
fully, be mistaken for colostrum. Bloody milk produced by an 
inflamed udder may be distinguished by small blood particles, 
which will settle to the bottom, and can be noticed if the sample 
is placed in a glass test-tube. In bloody milk caused by bacterial 
growth the blood does not show at the bottom, but instead, 
previous to stirring the milk or cream, it appears on the surface 
in small red dots. The red color which commonly occurs in milk 
is due chiefly to a species of germ called Micrococcus prodigiosus. 



68 ABNORMAL MILK 

Colostrum will show reddish cream on the surface, but no blood- 
like material will separate out. 

Blue Milk. — Blue milk is quite commonly found. Formerly 
it was thought that this color was due to the condition of the 
casein in the milk, but since more has been discovered in regard 
to the effect of germ life upon conditions and properties of milk, 
it has been proved that blue milk is caused by bacteria ^ {Bacillus 
cyanogenus). This particular germ produces the blue color in 
the milk only when the milk has an acid reaction. When sterile 
milk is inoculated with this particular germ, the blue color is not 
produced, but by the addition of a little acid, or by inoculating 
the milk with the bacteria that produce lactic acid, the blue color 
is produced. This seems to be one of the instances of sjnnbiotic 
action of bacteria in milk. There are probably other causes, 
but they are not known. This germ, according to Aikman, is 
killed by heating the milk to about 176° F. The germ ceases to 
work as soon as milk is coagulated. 

Yellow Milk. — According to Aikman,^ yellow milk is caused 
chiefly by one species of bacteria, named Bacillus synxanthus. 
This micro-organism belongs to the group of ferments that act 
upon the fat of milk. There are different shades of yellow pro- 
duced in milk, caused by different species of bacteria, but the 
above-mentioned one is considered to be the principal cause. 
Some produce a brilliant yellow color, while other species first 
curdle the casein, and then digest or dissolve it into a yellow or 
amber-colored liquid. 

Ropy Milk. — Slimy or ropy milk is not common, but is 
sometimes encountered by milk-dealers and is caused by certain 
micro-organisms. Aikman mentions the fact that no less than 
eighteen different and distinct organisms have been identified as 
associated with this sHmy fermentation. Most of the investi- 
gators agree that two organisms are chiefly responsible for the 
slimy condition. One of these is Bacillus lactis viscosus,'^ which 
grows best in the presence of air and neither forms acid nor thrives 
in an acid medium. This germ has been found to be frequently 

1 C. M. Aikman, in " Milk, Its Nature and Composition." 

2 Adametz, Landw. Jhr., 1891, p. 185. 



BITTER MILK 69 

present in surface waters. Bouska broke off a sliver from a 
water tank which, when put into milk, inoculated it with an 
organism that produced ropiness. The very fact that milk 
dealers in cities are occasionally troubled with this sliminess in 
milk indicates that precautions are essential in order to avoid the 
presence of this ferment. The germ, when it once gains 
entrance to a milk establishment, is very difficult to eradicate. 
In order to overcome the trouble it may be necessary to cover 
the whole inside of the milk-store, and all of the vessels used 
for handling the milk, with sour coagulated milk. The lactic 
acid germs present in this milk gain ascendency over the germs 
causing sliminess and in that way the trouble may be eradicated. 

Streptococcus hollandicus ^ is another species which produces 
sliminess in milk. It differs from the ferment mentioned above 
in that it grows in the absence of air and produces acid. It is 
used in Holland, in the preparation of the slimy whey (lange 
Wei) starter which is added to milk used in the manufacture 
of Edam cheese, just as we use a pure culture lactic acid 
starter in connection with Cheddar cheese-making. 

Sometimes milk is slimy when drawn from the cow — most 
frequently when there is inflammation of the udder. There 
are, in such cases, no bacteria present in the milk as the cause 
of the ropy or slimy condition. We quote Russell and Hast- 
ings: " The direct cause of the abnormal condition in milk is 
the presence of fibrin and white corpuscles from the blood, which 
form masses of slimy material; in such cases the trouble does 
not increase in intensity with age, nor can it be propagated by 
transference to another sample of fresh milk." 

Bitter Milk. — This is one of the most common kinds of abnor- 
mal milk, and like some of the others, may have more than one 
cause. It may be due to some undesirable food that the cow has 
eaten, or to the development of certain germs in the milk. If 
caused by the food eaten by the cow, the bitter taste is recog- 
nizable immediately after the milk has been drawn. If it develops 
on letting the milk stand, it is caused by bacterial growth. 

Several germs have been found to be associated with the pro- 

1 Milch Zeit., 1889, p. 982. 



70 



ABNORMAL MILK 




MILK FROM COWS WHICH HAVE BEEN IN MILK 71 

duction of this bitter flavor in milk. Conn has described a 
micrococcus which produces a bitter flavor, and Weigmann has 
described a bacillus which produces a similar effect. Nearly- 
all of the investigators agree that the germs causing the bitter 
flavors in milk belong to the group which acts upon the casein. 
The bitter flavor is most commonly found in milk that has been 
heated and then cooled to a low temperature. The heat destroys 
the bacteria that produce lactic acid, but does not kill those that 
produce the bitter flavor, owing to the fact that they are spore- 
producing. 

The germs that produce a bitter flavor do not develop in 
milk that is partly soured, because an acid reaction is unfavorable 
to their growth. 

It was formerly thought that the organisms that cause the 
bitter flavor in milk produced butyric acid. This theory, 
however, has been largely overthrown, as it has been found that 
these germs are chiefly of the kind which peptonize the casein 
and produce gas. 

Milk from Cows which Have Been in Milk for a Long Period.— 
The difference in the composition of the fat yielded by cows in 
different stages of the lactation period does not seem to affect 
the quality of the milk to a noticeable extent. If the cows have 
been giving milk an unusually long time, the milk may become 
abnormal. 

The impurities in the small amount of milk yielded by a cow 
almost dried up are quite apparent, and the causes of the presence 
of these impurities are readily understood. The small amount of 
milk drawn from such a cow would contain a proportionately 
larger amount of dirt and germs than would a larger amount of 
milk drawn from a cow yielding more milk, providing the cleanli- 
ness of the udder and manner of milking were the same. Cows 
giving a good quantity of milk always seem to have a cleaner 
udder. This has been laid to the more vigorous circulation of the 
blood in the udder of the cow that yields a larger portion of 
milk. 

When cows calve once a year, and have a rest of about seven 
weeks previous to parturition, if proper precautions are taken 



72 ABNORMAL MILK 

concerning cleanliness, they seldom yield milk from which a 
first-class quality of butter cannot be produced. In practice 
calving does not always occur at regular intervals. Several 
instances have come within the authors' notice where cows have 
been in milk for two years or more without coming in fresh. 
Such a condition happens quite frequently on small farms, where 
the cows kept are so few that it is deemed impracticable to keep a 
bull. As a consequence cows are not served at the proper time, 
and great irregularities in calving are introduced. 

At times it also happens that cows become barren. In such 
a case they are usually milked as long as they will produce even a 
very small quantity of milk. Milk produced under such con- 
ditions is likely to become abnormal in character. It may 
remain normal with a slight increase in the fat-content. The 
abnormal milk, so often complained of, is usually the result 
of similar circumstances. It is a common behef that milk 
yielded by such animals always contains a high fat-content, but 
it may contain very little fat, and may be salty. It may also 
appear normal, and the cream when separated appear viscous 
and dead. Boggild states that at the creamery the milk from 
one barren cow has more than once produced difficult churning. 

Milk from Spayed Cows. — H. Lennat has given this kind of 
milk considerable study. He finds that milk from spayed cows 
may vary in quality to the same extent as milk from normal cows. 
The solids of milk, as a rule, increase as the spayed cow advances 
in the milk-giving period. This is especially noticeable in the 
fat, sugar, and casein. Such milk is considered to be of extra 
good quality, and is recom^mended as being especially suitable 
for infant-feeding. 

Milk from Sick Cows. — Too much cannot be said against the 
use of milk from sick cows. As soon as the cows decline in health, 
the quantity is noticeably decreased, and the quality is usually 
abnormal. The kind of milk yielded varies with different cows 
and different diseases, but it is interesting to note from the 
study of this subject, by several men, that the milk-secreting 
glands are quickly affected by disease and are unable to perform 
their proper functions. Even a slight derangement of the 



MILK FROM SICK COWS 73 

digestive organs may have a marked iniluence upon the flavor 
of the milk and butter. When cows do not clean well after 
calving, the milk secreted by them always has an undesirable 
taste. During the time of sexual excitement of the cow, milk is 
usually decreased in quantity, and in a great many instances 
possesses a very disagreeable flavor. 

When a cow's udder is inflamed, the milk usually assumes 
an abnormal condition. It usually contains large, white slimy 
lumps. According to Bang,^ this condition is caused by a small 
round bacterium, and is contagious. When this germ is inocu- 
lated into the udder, the cow becomes feverish and the milk slimy. 

When cows become infected with tuberculosis to such an 
extent that the udder shows lesions and nodules, the composi- 
tion and appearance of the milk is altered considerably. Milk 
from such cows contains tubercle germs, appears yellowish- 
brown in color, and has an alkaline reaction. The composition 
of such milk has been studied in Denmark and reported by 
Boggild to be as follows : 

Water ; . 88 . 57 

Fat 3.55 

Albuminoids 5-69 

Sugar ■ 1-25 

Ash : 94 

These results represent the average of four samples taken from 
the diseased part of the udder. It will be seen that the greatest 
variation from normal milk consists in the small amount of sugar 
it contains and the high per cent of ash and nitrogenous matter. 
1 Maelkeribruget i Denmark, by Boggild. 



CHAPTER VII 

VARIATION OF FAT IN MILK AND CREAM 

As the variations in the per cent of fat in milk and cream are 
due to such widely different causes, it has been found expedient 
to divide this chapter into two parts. 

PART I 

VARIATION OF FAT IN MILK 

The percentage of fat in normal milk varies a great deal 
more than that of any of the other constituents. Dr. Richmond 
reports that the fat of milk may go as low as 1.04 per cent and 
as high as 12.52 per cent. Such extreme variations are, of course, 
abnormal. The fat-content seldom falls below 2I per cent or 
rises above 7 per cent. The fat-content of milk from a whole 
herd of cows varies only within comparatively narrow limits. 
The following are the chief factors which cause the fat-content 
of milk to vary : 

(i) Individuality of cows. 

(2) Breed of cows. 

(3) Time between milkings. 

(4) Manner of milking. 

(5) Whether the milk is fore or after milk. 

(6) Age of cow. 

(7) Advance in lactation. 

(8) Feed of cows. 

(9) Environment. 
(10) Condition of cow. 

I. Individuality. — Whether a cow will produce milk with a 
high or low fat-content depends upon something that is inherent 
in the individual animal. Cows in the same herd, under the same 

74 



VARIATION OF FAT IN MILK 



75 



conditions as to care, feeding, etc., will produce milk that differs 
widely in this respect. The secretory organs of the mammary 
gland are the large controlling factor, and these we cannot 
change. Even in the same breed we find animals that differ 
very widely, as the table below, compiled from complete records 
by Eckles, will indicate. These are average yearly tests for the 
highest and lowest testing animals in each breed. 



Breed 



Jersey. . . . 
Shorthorn 
Holstein. . 



Number 


Highest 


Lowest 


of 


Per Cent 


Per Cent 


Cows 


of Fat 


of Fat 


76 


7.00 


4-47 


25 


4-31 


3 59 


40 


3-8i 


2.60 



2. Breed of Cows. — The different breeds of dairy cattle have 
their distinctive '' breed characteristics," and the most important 
of these are the quantity of milk they produce and its richness in 
butter-fat. 

The Channel Island breeds — ^Jersey and Guernsey — are 
noted for the high fat-content of their milk; the milking strain 
of Shorthorns and the Ayrshire breed produce a milk of medium 
richness, while the Holstein produces a milk somewhat lower in 
fat content. As to quantity of milk produced the order reverses 
itself. 

For all the breeds, excepting the Milking Shorthorn, the 
table which follows, giving the average production and composi- 
tion of the milk of the different breeds, is based upon Bulletin 156 
of the Bureau of Animal Husbandry of the U. S. Department of 
Agriculture, which summarizes and digests the published reports 
of all the American experiment stations upon this subject. 

3. Time between Milkings. — Where cows are milked twice a 
day — the common practice in the United States and Canada — 
the difference in the per cent of fat in the two milkings is quite 
marked, if the intervals are very unequal. On the other hand, if . 
the intervals are equal, or nearly so, the difference is not great. 



76 VARIATION OF FAT IN MILK AND CREAM 

AVERAGE COMPOSITION OF THE MILK OF DIFFERENT BREEDS 



Breed 



Jersey. 

Guernsey 

Ayrshire 

Holstein 

Milking Shorthorn . 



Yearly 






Milk 


Per Cent 


Pounds 


Yield, 


of Fat 


of Fat 


Pounds 

SSoS 






5 14 


283 


5509 


4.98 


274 


6533 


3.8s 


252 


869Q 


3-45 


300 


5500 


4.00 


220 



Per Cent 
of Total 

Solids 



14.9 
14. 2 
9 
3 



13 



Experiments made by Ingle bring these points out quite clearly. 
Five cows were milked at 6 a.m and 3 p.m. during a period of 
three weeks. The average fat-content of the evening's milk 
was 4.26 per cent, while that of the morning's milk was 2.8 per 
cent. Following this, for four weeks, the cows were milked at 
5.30 A.M. and 5 P.M. and the average evening and morning tests 
were 3.80 per cent and 3.18 per cent respectively. Even here 
there was a difference of an hour in the length of the two inter- 
vals, which would account, largely, for the difference in test. It is 
claimed, however, that with equal intervals the evening's milk will 
test slightly higher than the morning's milk. This is attributed 
to greater activity of the fat-secreting cells when the cows them- 
selves are more active. 

Milking three times a day, as is the custom in Denmark, 
increases, to some extent, both the quantity of milk produced 
and the per cent of fat in it. But the increase is not sufficiently 
marked to induce the average farmer in America to adopt this 
practice, except in the case of a cow which is an exceptionally 
large producer. 

4. Manner of Milking. — Milking should be done in such a 
manner as to induce the cow to be sympathetic toward the 
milker. Hand milking should be performed quickly, but not 
roughly or in a way that will excite the animal or create discom- 
fort. The hand should close regularly and quickly from above 
downward, in such a way as to extract the milk quickly and 
efficiently. The finger ends should not press into the teats 



VARIATION OF FAT IN MILK 



•77 



uncomfortably, nor should the nails come into contact with the 
teat to the extent of irritating it. As will be seen in dealing 
with fore and after milk, the milking must be done thoroughly 
since the strippings are very rich in fat content. 

There is a marked difference between milkers. On this point 
we quote from Decker. " By looking over the milking records 
of the University of Wisconsin, it was possible to pick out the 
cows milked by a certain milker, for he could (or rather did) 




Fig. 13. — ^The wrong way to milk cows. (From Glucose Sugar Refining 

Catalogue.) 

invariably get more and richer milk from the same cows than 
when the cows were milked by other men." 

5. Fore and After Milk. — The first milk drawn from a cow is 
very low in fat content, containing just a few tenths of a per 
cent of fat; while the last, the strippings, will test very high, 
often up to 8 to 10 per cent. 

Van Slyke of the New York Station analyzed the different 
portions of the milk of a Guernsey cow, with the following 
results: 



78 



VARIATION OF FAT IN MILK AND CREAM 



First portion. . 
Second portion 
Third portion . 
Fourth portion 



Pounds 


1 
Per Cent 


of Milk 


of Fat 


3-2 


o. 76 


4-1 


2.60 


4.6 


5-35 


5-8 


9.80 



The practical lesson to be drawn from this is that milking 
should be done efficiently and completely. 

6. Age of Cow. — As already pointed out, the richness of a 
cow's milk is very largely determined by heredity. She will not 
produce rich milk during one lactation period and poor milk 
during another. However, age has its influence. Normally 
there is a marked increase, from year to year, in the quantity of 
milk given, with a tendency to a slight increase in the fat-content, 
until a cow reaches maturity. Then, in the ordinary course of 
events, we may look for a gradual decline. The following is 
quoted from Eckles, whose investigations were both extensive 
and thorough: "On the average, a well-grown two-year-old 
may be expected to produce 70 per cent, a three-year old 80 
per cent and a four-year old 90 per cent of the milk and fat that 
she will produce when mature." " The average fat-content 
remains practically constant from year to year, except that after 
the cow is eight or nine years old the percentage of fat always 
declines slowly and gradually with advancing years." 

7. Advance in Lactation. — This is a factor that materially 
influences both the quantity of milk produced and its fat-content. 
When a cow freshens she will probably, if in reasonably good 
condition, produce milk with a slightly higher per cent of fat in it 
than there will be a Httle later. With this exception the quan- 
tity of milk produced and the per cent of fat in it usually remain 
fairly constant during the first three or four months, after which 
there is a gradual decline in the quantity of milk produced and a 
steady increase in its richness. But cows differ very widely in 
the rate of increase in the fat-content of their milk as they 
advance in their lactation period. The following table gives the 



VARIATION OF FAT IN MILK 



79 



records of two cows in the same Canadian herd, both of which 
freshened in the spring and at practically the same time — also 
the average for fourteen cows at the Geneva Station : 





Cow No. I 


Cow No. 2 


Geneva 


1^14 cows) 


Month 












No. 


Pounds 


Per Cent 


Pounds 


Per Cent 


Pounds 


Per Cent 




of Milk 


of Fat 


of Milk 


of Fat 


of Milk 


of Fat 


I 


546 


3-4 


614 


3-3 


753 


4.02 


2 


618 


3-4 


704 


3 


2 


780 


3 


74 


3 


622 


3-5 


714 


3 


7 


714 


3 


71 


4 


723 


3-5 


721 


3 


8 


636 


3 


84 


5 


714 


3-7 


693 


4 


I 


588 


3 


87 


6 


636 


3-9 


627 


4 


4 


594 


3 


90 


7 


601 


4.0 


591 


4 


6 


570 


3 


94 


8 


540 


41 


502 


5 


I 


480 


3 


89 


9 


427 


4-1 


461 


5 


3 


375 


3 


92 


lO 


214 


4.2 


47 


7 


6 


282 


4 


19 


II 












168 


4 


58 







8. Feed of Cows. — There was at one time a very general 
belief, which still has its advocates, that the per cent of fat in 
milk varies with the nature of the food the cow receives; but 
many investigations made both in America and in Europe have 
shown that, practically speaking, the richness of a cow's milk is 
not influenced by her food. A narrow ration, one made up 
quite largely of concentrates rich in protein, will stimulate the 
milk flow, a fact which is well known and made use of by those 
experienced in the fitting and feeding of cows for high official 
records; but it does not increase the per cent of fat in the 
milk. 

Observations by the Copenhagen (Denmark) Station over a 
period of ten years, and including about 2000 cows, led the 
observers to conclude that foods high in protein content may 
possibly raise the fat-content of the milk to the extent of o.i 
per cent — a very slight increase if actually an increase at all. 
Lindsay of the Massachusetts Station found that a ration with a 



80 VARIATION OF FAT IN MILK AND CREAM 

large excess of protein stimulated the milk flow to the extent 
of 15 per cent, but he concluded that the per cent of fat in the 
milk is not influenced by the food a cow receives. 

The addition of such abnormal foods as tallow, lard, pahn 
and oleo oils to a cow's ration, or such a radical change of food 
and environment as from stable to pasture conditions, may cause 
a temporary change in the per cent of fat in a cow's milk, but the 
change is only temporary. 

9. Environment. — Such unfavorable conditions as exposure 
to inclement weather, sudden changes in temperature, and poorly 
ventilated barns will cause a decrease in the milk flow. Experi- 
enced cheese and butter-makers have noted a very serious falling 
off in the output of their factories within a comparatively short 
time, when the cows were exposed to low temperatures and cold 
storms. Under continued exposure to unfavorable environment 
there may be, at first, a temporary increase in the per cent of fat 
in the milk. 

Reasonable exercise, under suitable weather conditions, is 
favorable to both health and a large production, but excess of 
exercise is not desirable. Where cows are confined to the stable, 
without exercise, the production may be quite satisfactory, but 
these conditions are detrimental to the health of the animal and, 
in the authors' opinion, are contributory to the spread of tuber- 
culosis in a herd. In Denmark it is the common practice to keep 
the cows closely confined, without exercise, during the winter 
months, and tuberculosis is very prevalent amongst the herds of 
that country. 

To secure the best results we must study the comfort of the 
animal, and under the head of comfort we include favorable 
temperature, clean healthful surroundings and the avoidance of 
rough treatment and excitement. 

ID. Condition of Cow. — If a cow be in a high state of flesh 
when she freshens, her milk wiU test much higher during the first 
few weeks than it otherwise would. Investigations made by 
Professor Eckles of Minnesota University bring this point out 
very clearly. We submit the following table based upon work 
done by him: 



VARIATION OF FAT IN CREAM 



81 



Time after 


No. 207 


No. 217 


No. 300 


Calving 








Days 


Per Cent 


Per Cent 


Per Cent 


2 


5-8 


4.4 


4-5 


s 


4.8 


4.2 


4.2 


lO 


3-9 


3-5 


4-1 


15 


3-2 


3-7 


3-9 


20 


2-5 


3-4 


3-6 


Months 








3 


2.6 


3-0 


3-6 


6 


2.4 


3-5 


4.0 


9 


3-0 


3-4 




12 


3-3 


4-1 




Aver, for Year 


2.8 


3-4 


3-55 



Compare the first part of this table with that of the preceding 
table in connection with " Advance in Lactation Period." 

On the other hand, Eckles found that when a cow begins to 
put on flesh there is the very opposite tendency, namely, for the 
per cent of fat in her milk to decKne. 



PART II 

VARIATION OF FAT IN CREAM 

The percentage of fat in cream delivered to creameries or for 
city trade varies considerably from day to day, and a great deal 
of dissension arises from the fact that the producer does not always 
understand all the factors that are responsible for this wide 
variation. 

Extensive work has been done by Professor O. F. Hunziker, 
Purdue University, and similar work has been carried on at the 
Danish Experiment Station at Copenhagen. The work done at 
Purdue and other experiment stations plainly and conclusively 
shows that there are a great variety of factors and conditions 
which control the richness of cream. These factors influence the 
richness of the cream before it leaves the farm and cannot be 



82 VARIATION OF FAT IN MILK AND CREAM 

controlled by the creamer3mian, who receives the cream after it 
has been separated. It is physically impossible to produce 
cream of exactly the same richness from different skimmings 
under the gravity method of creaming. It is impossible to so 
operate the spoon, ladle or skimmer as to remove the same 
amount of skim-milk with the cream each time. Where the 
skim-milk is drawn from the bottom of the can it is equally 
impossible to so gage the operation as to leave cream of the same 
richness in the can at each skimming. Gravity cream, or cream 
obtained by gravity skimming, is sure to vary in richness, and it 
is not difhcult for the producer to realize the causes of variations 
under this method of creaming. It is more difficult, however, 
to convince him that the richness of the cream will vary where the 
small centrifugal or farm separator is used. The separator is one 
of the most perfect pieces of farm machinery in use, and is 
accordingly expected to do nearly perfect work. It is only 
reasonable that the user of the small centrifugal machine will 
expect to produce a uniform quaHty of cream; hence, when he 
sells this cream and finds that the test is not the same as it was 
on the previous day he suspects that something is wrong. The 
small farm separator does produce the same richness of cream 
from different skimmings, provided that it is adjusted properly, 
that it is operated in strict accordance with directions which 
accompany it, and that the richness, condition and temperature 
of the milk, and the proportion of water or skim-milk used in 
flushing the bowl to the amount of milk separated, are the same. 
The following are the chief factors which influence the per cent 
of fat in cream: 

(i) Cream screw adjustment. 

(2) Richness of milk. 

(3) Rate of inflow. 

(4) Speed of machine. 
(3) Temperature of milk. 

(6) Amount of water or skim-milk used to flush the bowl. 

I. The Cream Screw. — The richness of the cream obtained 
from any farm separator is primarily determined and regulated 



VARIATION OF FAT IN CREAM 83 

by the cream screw. The centrifugal separator has two main 
outlets, namely, the skim-milk outlet located near the periphery 
or outer wall of the bowl, and the cream outlet, located near the 
center of the bowl. 

When the milk enters the revolving bowl it is separated into 
two layers, the skim-milk and the cream. The skim-milk, being 
heaviest, is thrown against the walls of the bowl where it escapes 
through the skim-milk outlet. The cream is drawn toward the 
center of the bowl, where it rises and is discharged through the 
cream screw or cream outlet. The cream screw is a small 
threaded bolt with a very minute opening. This bolt can be 
turned so as to move the opening nearer or farther from the cen- 
ter of the bowl. When turned toward the center it delivers 
richer cream, because a smaller proportion of the milk is taken 
as cream. When turned out from the center it delivers thinner 
cream, because a larger proportion of the milk is taken as cream. 

2. Effect of Richness of Milk on Richness of Cream. — The 
richer the milk, the richer will be the cream. With the cream 
screw set to deliver a certain and definite richness of cream and 
all other conditions normal, the separator will deliver a definite 
ratio of skim-milk and cream. This ratio varies according to the 
way the cream screw is set. Under average conditions it may be 
about 85 to 15; that is, for each 100 pounds of milk separated 
the separator delivers 85 pounds of skim-milk and 15 pounds of 
cream. If all conditions are the same, this ratio of skim -milk 
to cream remains constant. Changes in the richness of the milk 
cannot alter the proportion of skim-milk to cream delivered. 
No matter how rich or how poor the milk, each 100 pounds 
of milk will yield 85 pounds of skim-milk and 15 pounds of 
cream. 

But because practically all of the fat goes into the cream, the 
cream will contain more fat from the separation of rich milk 
than from that of thin milk. This fact is graphically illustrated 
in Fig. 14. 

The illustration (Fig. 14) conclusively shows that, all other 
conditions being the same, 3 per cent milk produces 20 per cent 
cream, 4.5 per cent milk produces 30 per cent cream, and 6 per 



84 



VARIATION OF FAT IN MILK AND CREAM 



cent milk produces 40 per cent cream. Changes in the richness 
of milk cause changes in the richness of the cream. Any condi- 



EFFECT OF RICHNESS OF MILK UPON THE CREAM 



100 LBS. OF Sfc MILK 
CONTAINS 3 LBS. OF FAT 



85 LBS. 
SKIM-MILK 



15 LBS- OF CREAM = 3 LBS. OF FAT 
TEST OF CREAM =20^ 
-, JX 100 = 205s 



100 LBS. OF 4,5^ MILK 
CONTAINS 4.5 LBS. OF FAT 



85 LBS. 
SKIM-MILK 




1 5 LBS. OF CREAM =4.5 LBS. OF FAT 
TEST OF CREAM =:30Ji 
tf X 100 = 30/c 



lOO LBS. OF 6^ MILK 
CONTAINS 6 LBS. OF FAT 



85 LBS. 

SKIM-MILK 



15 LBS. OF CREAM = 6 LBS. OF FAT 
TEST OF CREAM =4 0f2 
Y^x 100 = 405^ 



Fig. 14. 

tion, therefore, that affects the richness of the milk will also influ- 
ence the richness and the test of the cream. 

Conditions that May Cause Changes in the Richness of the 
Milk. — During the early summer months the milk is usually 
comparatively low in butter-fat. This is caused by such factors 
as the freshening of the cows, change from dry feed to succulent 
pasture and a natural and inherent tendency of the cows toward a 
decrease in the richness of their milk in early summer. Toward 
fall and early winter the opposite is the case. The advanced state 
of the period of lactation and the change from succulent to dry 
feed cause the milk to become richer in fat. It is obvious, there- 
fore, that in the fall and winter the cream test tends to be higher 
than in spring and early summer. 

Again, it frequently happens that even in winter there is a 
sudden drop in the cream test. This may be due to the fact 
that some of the cows yielding rich milk dry up or that some cows 
come in fresh or a new animal may be brought into the herd. 

The seasonal variations in the richness of the cream may be 
reduced by turning out the cream screw a trifle in the fall and by 
turning it in during the spring of the year. 



VARIATION OF FAT IN CREAM 



85 



3. Effect of Rate of Inflow on Richness of Cream. — The 

greater the amount of milk passing through the separator of a 
definite capacity per hour, tlie thinner will be the cream. 

The skim-milk outlet of the bowl is constant. It can dis- 
charge so much skim-milk and no more. It offers the first avail- 
able exit for the milk in the bowl. Since it is located at the 
periphery of the bowl toward which the skim-milk is forced, it 
discharges skim-milk. 

All the milk that flows into the bowl in excess of what the 
skim-milk outlet can discharge, leaves the separator through the 



EFFECT OF RATE OF INFLOW UPON RICHNESS OF CREAM 



NORMAL INFLOW 

300 LBS. OF 4ft MILK 
CONTAINS 12 LBS. OF FAT 



255 LBS. 
SKIM-MILK 



TEST OF CREAM =26.7^ 
1% X 100 =26.75^ 



LARGE INFLOW 

350 LBS. OF 4;^ MILK 
CONTAINS 14 LBS. OF FAT 



255 LBS. 
SKIM-MILK 



TEST OF CREAM =14. 7; 

4^x 100 =14. 75$ 



SMALL INFLOW 

270 LBS. OF 4% MILK 
CONTAINS 10.8 LBS. OF FAT 



255 LBS, 
SKIM-MILK 




TEST OF CREAM =72^^ 



Fig. 15. 



cream outlet or the cream screw. The cream outlet, being located 
near the center of the bowl where the cream gathers, delivers 
cream. 

The cream outlet then serves as the overflow. The greater 
the amount of milk running into the bowl in excess of the capacity 
of the skim-milk outlet, the greater is the overflow, the more 
milk will leave the bowl through the cream outlet and the thinner 
will be the cream. If the separator is so adjusted that, under 
normal conditions, each loo pounds of milk produces 85 pounds of 
skim-milk and 15 pounds of cream, a 300-pound capacity machine 



86 VARIATION OF FAT IN MILK AND CREAM 

will deliver 85X300-^100 or 255 pounds of skim-milk and the 
remainder, the overflow, will be cream. In this case the amount 
of cream discharged will be 45 pounds (300 — 255=45). If the 
separator is forced beyond its capacity, that is if more than 300 
pounds of milk are run into the machine, the skim-milk dis- 
charged remains the same and the cream discharged receives the 
extra milk. Running 350 pounds of milk into the machine, 
for example, causes the separator to yield 255 pounds of skim- 
milk and 95 pounds (350 — 255 =95) of cream. If the milk inflow 
is reduced below the capacity of the cream, say to 270 pounds, 
the skim-milk discharged remains the same (255 pounds) and 
the cream discharged is 15 pounds (270 — 255 = 15). The effect 
of these variations in the rate of inflow on the richness of the 
cream is shown in Fig. 15. 

The above diagram shows that almost any richness of cream 
may be obtained from the same milk and the same separator 
according to the amount of milk that flows into the bowl per hour. 
A normal inflow produced 26.7 per cent cream, a large inflow 
produced 14.7 per cent cream and a small inflow produced 
72 per cent cream. 

Even the fullness of the pan or tank from which the milk 
runs into the bowl affects the richness of the cream. The fuller 
the tank the more rapidly will the milk flow into the bowl owing 
to a few inches of additional pressure. If the tank is kept filled 
to the brim the cream will be thinner than when the tank remains 
only one-third full. 

Every separator is equipped with a simple device called the 
" Float " to regulate the inflow. The float fits into the receiving 
cup of the bowl. When too much milk flows into the bowl the 
float rises and partly shuts off the outlet of the milk supply tank. 
When too little milk runs into the bowl the float recedes and the 
supply tank delivers more milk. 

The simplicity of the float has had a tendency to behttle its 
value in the mind of the average dairyman, with the result that 
on many farms it is not used and has been discarded. Bearing 
in mind the marked effect of the rate of inflow on the richness of 
the cream it seems inconsistent to accuse the creamery of inac- 



VARIATION OF FAT IN CREAM 



87 



curate testing when the separator float is a conspicuous part of 
the scrap pile on the farm. 

4. Effect of Speed of Machine on Richness of Cream. — The 

speed of the revolving bowl produces the force — centrifugal force 
which drives the skim-milk out of the bowl. The greater the 
speed, the greater the centrifugal force and the more rapidly 
the skim-milk leaves the bowl. An increase in the speed, there- 
fore, forces more skim-milk through the skim-milk outlet. 
This means less milk for the cream outlet and consequently 



EFFECT OF SPEED UPON THE RICHNESS OF CREAM 



NORMAL SPEED 

100 LBS. OF 4.4^ MILK 
CREAM CONTAINS 4.4LBS.FAT 



LOW SPEED 

100 LBS. OF 4.4J? MILK 
CREAM CONTAINS 2.-1 LBS.FAT 



10 LB 



90 LBS. 
SKIM-MILK 




TEST OF CREAM =44? 



HIGH SPEED 

100 LBS. OF 4.4,^ MILK 
CREAM CONTAINS 4.4 LBS. FAT 



81 LBS. 
SKIM-MILK 




TEST OF CREAM =1 1J 
SJ-X 100 =115^ 



93 LBS. 
SKIM-MILK 



TEST OF CREAM =63? 



:63?S 



Fig. 16. 



richer cream. A decrease in the speed forces less skim-milk 
through the skim-milk outlet, more milk has to be discharged 
through the cream outlet and the cream, therefore, is thinner. 

These facts were established experimentally. A separator 
was so adjusted that, when run at normal speed (60 turns of 
crank per minute), it delivered 90 pounds of skim-milk and 10 
pounds of cream. When the speed was lowered to 25 turns of the 
crank per minute, the skim-milk outlet discharged only 81 pounds 
of skim-milk, increasing the amount of cream delivered to 19 
pounds. When the speed was raised to 75 revolutions per 
minute, the skim-milk discharge increased to 93 pounds, reducing 



88 VARIATION OF FAT IN MILK AND CREAM 

the amount of cream to 7 pounds. The effect of these variations 
of speed on the richness of the cream are shown in Fig. 16. 

Fig. 16 demonstrates conclusively that high speed yields rich 
cream and low speed yields thin cream. At normal speed, the 
cream tested 44 per cent fat, at low speed 1 1 per cent fat, and at 
high speed 63 per cent fat. The very low test of cream from a 
low speed separation is, in part, due to the fact that a large 
amount of fat (about one-half of the fat of the milk) is lost in the 
skim-milk. 

How to Run the Separator at the Right Speed. — The proper 
speed is indicated on the crank of the machine. It varies from 
about 40 to 60 turns of the crank per minute, according to the 
make of the separator. If a separator is to yield cream of uniform 
richness, it must be given the same speed at each skimming. 
This is possible only if the operator times himself frequently, 
counting the revolutions of the crank with watch in hand, or by 
the use of a patent speed indicator. The absence of this pre- 
caution renders the work unreliable. The general tendency on 
the part of the operator is to overestimate the amount of work he 
puts into the machine; the machine is run at too low a speed. 
Even the same operator may vary the speed very considerably 
at different times, depending on his frame of mind and physical 
condition. Again, where different persons operate the machine, 
there can be but Httle uniformity of speed, unless each person 
makes an effort frequently to count the crank revolutions by the 
watch. The use of a gasoline engine or some constant power 
will tend to give a more uniform cream than when the machine is 
operated by hand. 

5. Effect of Temperature on Richness of Cream. — The higher 
the temperature the thinner the cream. The temperature 
influences the rate of inflow. The warmer the milk the more 
rapidly will it run from the supply tank into the bowl. Since 
the capacity of the skim-milk outlet is fixed, the increased inflow 
of the milk is discharged through the cream outlet, producing a 
thinner cream. Experimental results showed that when the 
separator was so adjusted as to yield 15 pounds of cream and 
85 pounds of skim-milk from every 100 pounds of milk separated 



VARIATION OF FAT IN MILK AND CREAM 



89 



at 90° F., a drop in the temperature to 50° F., caused the 
amount of cream dehvered to decrease to 5.5 pounds and the 
skim-milk to increase to 94.5 pounds. These results are graph- 
ically illustrated in Fig. 1 7. 

The results expressed in Fig. 1 7 show that when the tempera- 
ture of the milk is decreased below normal, the richness of the 
cream increases. At 90° F., the cream contained 26 per cent fat. 
At 50° F. it contained 40 per cent fat. The increase in the test 
of the cream from the cold milk would be still greater, if it were 



EFFECT OF TEMPERATURE UPON RICHNESS OF CREAM 


TEMPERATURE OF MILK 90-95° F. 


TEMPERATURE OF MILK 50°F. 


100 LBS. OF 3.9,^ MILK 


ICQ LBS. OF 3.9^ MILK 




CREAM CONTAINS 3.9 LBS. FAT 


. CREAM CONTAINS 2.2 LBS. FAT 




^^^ 




r 




mmmmm 




J 


50 

[40^ 


j 


50 
40 
30 

265i 


94.5 LBS. 


85 LBS. 




SKIM-MILK 




s 




SKIM-MILK 




1 


J 


1 5 LBS. CREAM COMTAIimS 3.9 LBS. FAT 


S.5LBS. CREAM CONTAINS 2.2 LBS. FAT 


TEST OF CREAM =26^ 


TEST OF CREAM =40^ 


ff x100=25j{ 


f|x 100=40^ 



Fig. 17. 

not for the fact that at that temperature a large amount of fat 
is lost in the skim-milk. 

The Proper Temperature for Separation. — The best practical 
temperature at which to separate the milk on the farm is about 
90° F. The milk is never in better condition for separation than 
immediately after it is drawn. It then has a temperature of 
about 90° F. to 95° F. If the milk is allowed to cool to a much 
lower temperature, as is the case in the winter, when the separator 
is operated only once per day, or once in several days, it should be 
warmed up to about 90° F. before it is run through the separator; 
otherwise there is bound to be a considerable variation in the 
cream test and also an increased loss of fat in the skim-milk. 



90 VARIATION OF FAT IN MILK AND CREAM 

6. Effect of Amount of Water or Skim-milk Used to Flush the 
Bowl. — The more water or skim-milk used to flush the bowl, the 
thinner will be the cream. 

At the conclusion of the separation there remains in the bowl 
and in the cream-discharging pan a considerable quantity of 
cream. In order to save this cream it is necessary to flush the 
bowl with water or with skim-milk. If enough water or skim- 
milk is used the cream remaining in the separator is flushed out 
and discharged into the cream can. 

The extent to which the cream test is lowered by flushing the 
bowl will depend on the amount of water or skim-milk used, the 
manner in which it is added and the amount of milk separated. 

If just enough water or skim-milk is used to thoroughly rinse 
out the bowl and the pan or tank, the richness of the cream is 
not materially changed. An excess of water or skim-milk may 
cause a considerable decrease in the richness of the cream. 

If the water or the skim-milk is poured into the supply tank 
and is allowed to run into the machine gradually, most of it will 
escape through the skim-milk outlet and the richness of the cream 
will be changed but very Httle. If the water or skim-milk is 
poured directly into the receiving cup of the bowl, with the float 
discarded, it will run into the bowl much more rapidly and more 
of it will get into the cream. 

The smaller the amount of milk used for the separation, the 
more the cream is thinned down by the flushing. 

Experimental data show that the cream test may be lowered 
from I to lo per cent according to the amount and conditions of 
the flushing. Enough water or skim-milk has been used when 
the cream discharge begins to appear watery. Hot water or 
warm milk will drive the cream out of the bowl more quickly and 
may produce a higher testing cream. 

The Proper Richness of the Cream. — Too thin cream is not 
satisfactory because it leaves but a small amount of skim-milk 
for the use of the dairy farmer, it increases the cost of transpor- 
tation, it sours and spoils more rapidly, it prohibits the use of a 
reasonable amount of starter for ripening at the creamery, it 
does not churn out exhaustively, and 3delds an excessive amount 



VARIATION OF FAT IN CREAM 91 

of buttennilk, augmenting the loss of fat and therefore reducing 
the churn yield. 

Too thick cream is undesirable because it may cause the sep- 
arator to clog, it increases the loss in handHng, it is difficult 
to properly sample and interferes with the accuracy of the test. 

The most satisfactory cream for butter-making is that which 
tests about 30 to 40 per cent fat. It is desirable to produce 
somewhat richer cream in summer than in winter to prevent 
excessive souring in summer and difficult handling in winter. 

Effect of These Factors upon the Skimming Efficiency of the 
Separator. — The richness of the milk has no effect on the com- 
pleteness of the skimming. 

The richness of the cream, within reasonable limits, has no 
effect on the completeness of the skimming. The skimming of 
very rich cream causes a large loss of fat in the skim-milk in the 
case of certain makes of separators, due to the clogging of the 
machine. 

The Rate of Inflow Greatly Affects the Completeness of the 
Skimming. — If more milk is run into the machine than the capac- 
ity of the machine calls for, there is excessive loss of fat in the 
skim-milk. If the rate of inflow is reduced below the capacity of 
the skim-milk outlet, the separator delivers no cream at all. 

The Speed of the Separator Greatly Influences its Skimming 
Efficiency. — Excessive speed does not increase the completeness 
of the skimming. Insufficient speed increases the loss of fat in 
the skim-milk. A separator run at half speed may cause one-half 
of the fat of the milk to be lost in the skim-milk. 

The Temperature of the Milk Affects the Skimming Efficiency 
of the Separator. — For all practical purposes a temperature of 
90° F. causes efficient skimming. At lower temperatures there is 
excessive loss of fat in the skim-milk. 

The Amount of Water or Skim-milk used to Flush the Bowl 
Regulates the Amount of Fat Lost in the Bowl and Pan. — If the 
bowl is not flushed at all, or insufficiently, varying amounts of 
fat may be lost. If the bowl is flushed until the cream discharge is 
watery, most of the fat in the bowl and pan is recovered and 
saved. 



CHAPTER VIII 

RECEIVING, SAMPLING, GRADING AND TESTING MILK 

AND CREAM 

Receiving and Grading of Milk and Cream. — The man who 

receives and samples milk at a creamery should be accurate and 
quick at figures, have abiHty to grade and select milk, and to 
stimulate interest in the production of good milk. He should 
also be able to reconcile and satisfy patrons. The method 
employed in some creameries of allowing a boy with immature 
judgment to weigh and sample milk should not be tolerated. 
The person who weighs and samples milk and cream comes in 
direct contact with the patrons. Therefore, he is a strong factor 
in serving the best interests of the creamery. In many of the 
best butter and cheese factories in the country the head maker 
or manager in charge is usually found at the weighing can. This 
gives him the opportunity of studying the raw material from which 
he is expected to make a high grade of butter or cheese. Some 
of our large central plants pay the highest salary to the man who 
has the ability properly to grade the cream and prepare the 
starters. This requires a fine sense of smell and taste, which is 
not possessed by everyone. 

The first step in the receiving of milk is to ascertain the quahty 
of the milk delivered by the patrons. It is now a recognized 
fact that the best butter cannot be produced from defective or 
abnormal milk or cream, no matter how many improved methods 
are employed in the manufacture. In view of this fact, and of 
the knowledge we now have of the transmission of undesirable 
germs from one sample of milk to another, and also the probability 
that some of the patrons will deliver poor milk, it is essential that 
the milk or cream be graded when it is delivered at the creamery. 

92 



RECEIVING AND GRADING OF MILK AND CREAM 93 

In the grading of milk or cream, different methods can be 
used for detecting abnormal milk: (i) through the senses, 
taste, sight, and smell; (2) by the acid tests; (3) by the fermenta- 
tion test; (4) by heating; (5) by the Babcock test and the lac- 
tometer. 

While all of these tests are applicable to the grading of milk, 
only the first and a portion of the fifth are usually applied to 
cream. 

I. Detection of Abnormal Milk and Cream through the 
Senses. — In order to detect the different kinds of defective milk 
one must be endowed with acute senses of smell, taste, and sight. 
When the milk is in a good condition, it has a pleasant smell and 
sweet taste, and appears normal. This applies equally to cream 
with the exception that not all cream for butter-making is sweet. 
If milk has a disagreeable smell and taste it cannot produce good 
butter. As a rule, the quantity of defective milk brought into 
the average creamery is much in excess of that of really perfect 
milk. As a consequence it would not be practicable to separate 
all the defective milk into one class and the perfect into another. 
The question as to where the line should be drawn between the 
good, medium, and very bad milk or cream, must depend 
upon the judgment of the receiver, and in a great measure upon 
the local conditions. Some of the creameries have no facilities 
for handling different grades of milk, and some sell butter on a 
market where no sharp distinction is made between good and 
poor butter. Others have, through experience, satisfied them- 
selves that under American creamery conditions it does not pay 
to make too many grades, nor does it pay to grade too closely. 
Two, or at the most three, grades of butter can at times be man- 
ufactured in one creamery profitably. It is advisable to reject 
sour and abnormal milk. If accepted, it should not be mixed 
with the remainder of the milk, as it might contaminate all of it; 
or, the sour milk might cause coagulation, and thereby clog up 
the separators. If a can of milk is sour, but otherwise clean, it is 
not necessarily unfit for the production of first-class butter. If 
retained until after the sweet milk has been skimmed, it may be 
run through the separator successfully. 



94 GRADING AND TESTING MILK AND CREAM 

2. The Use of Acid Tests. — Some creameries are now grading 
the milk or cream according to the amount of acid it contains. 
Mann's and Farrington's acid tests can both be used, but a more 
rapid and convenient way is to use a solution prepared from Far- 
rington's tablets. The solution is prepared by dissolving the 
tablet in warm water, using an ounce of water to a tablet. When 
one part of this alkaline solution and one part of milk are mixed 
together in a cup and the solution still retains a pink color, it shows 
that there is less than .i per cent acid in the sample tested. If 
two parts of alkaH and one part of milk are mixed and the mixture 
remains pink, then there is less than .2 per cent of acid. If the 
mixture becomes colorless, it shows there is more than .2 per cent 
acid in the sample. If three measures of alkali to one measure 
of milk are taken, and the mixture remains pink, there is less 
than .3 per cent of acid, etc. By means of such a test the acidity 
can quickly be determined. 

The sample cups should be numbered to correspond with the 
number of each patron. The results of the tests should be 
noticed at once, as the action of the atmosphere affects the color. 

The acid tests are of value in grading cream, as a sour sample 
of milk or cream is either old or has been improperly kept and 
handled. The number of grades of cream and milk and the max- 
imum limit of acid each grade can contain, are factors which 
must be decided according to local conditions, by the operator. 

3. Use of the Fermentation Tests. — Curdled, ropy, red and 
blue milk can, as a rule, be readily detected without the appli- 
cation of a special test, but there are cases when a person's 
senses are not sufficiently acute to detect samples of milk con- 
taining undesirable fermentations. Several instances have 
recently come within the authors' notice. A neighboring cream- 
ery was infested with a peculiar fermentation that caused a very 
rank flavor in the butter. The milk that came to the creamery 
was carefully examined, but the source of the trouble could not 
be located. The cause could not be ascertained without the use 
of the fermentation test. 

It is in such instances that a fermentation test is of special 
value. As a rule, the trouble is first caused by milk from one 



RECEIVING AND GRADING OF MILK AND CREAM 95 

particular patron. This milk may appear to be normal, and yet 
contain germs which are very undesirable for the manufacture of 
the best quality of butter. 

Fermentation Tests. — There are two tests which may be of 
general use; namely, the "Wisconsin Curd Test" and the 
" Gerber Fermentation Test." The former is used in cheese 
factories, but the latter is to be recommended in testing milk for 
butter-making. 

Gerber Test. — The apparatus for this £est consists of properly 
made glass tubes resting upon a rack which fits into a small 
round tin tank, about two-thirds full of water. The temperature 
of this water can be controlled by means of a lamp kept burning 
underneath, or by the use of steam. The milk delivered by dif- 
ferent patrons is put into the glass tubes, and these are numbered 
so as to indicate to which patron each belongs. The tempera- 
ture should be kept at about 104° to 106° F. for about six hours. 
Then the tubes are taken out, the milk shaken, and the appear- 
ance, smell, and taste of the milk noted. The tubes are warmed 
again for about another six hours, when they are again examined. 
If any samples contain a preponderance of abnormal ferments, 
the fact will usually appear in less than eighteen hours. If 
milk does not coagulate in twelve hours, or become abnormal 
in some way, it is considered good. 

The special apparatus mentioned above is not absolutely 
essential, nor is the temperature employed considered by the 
authors to be the most suitable to give reliable results. Ordinary 
sample jars can be used, instead of specially prepared tubes. 
After the milk has been placed in the jars they can be kept in any 
convenient place, at a temperature of about 98° F. The best 
place to keep them is in a vessel containing water, the temperature 
of which can be controlled. 

Wisconsin Curd Test. — ^This test consists of taking some milk 
in a jar and adding about ten drops of rennet, which coagulates 
the milk. The sample is allowed to stand until the curd hardens, 
when it is cut into small pieces with a case knife; the whey is 
drawn off, and the curd allowed to stand at a temperature of 
98° F. If there are any undesirable forms of bacteria present, 



90 



(IRADINO AND 'I'lvSTlNd MILK AND CRKAM 



they will reveal themselves by developing small holes in the curd, 
usually accompanied l)y a bad odor. 

This test is a very ingenious one for cheese-making. In 
butter-making the Gerber Fermentation Test, or a similar one, 
is more convenient. 

4. Grading Milk by Heating. — This test is not very much 




Fig. 18. — Trocmner's Babcock cream-testing scales. 

used in creameries ; but in cheese factories the heating of milk in 
order to ascertain its suitability for cheese-making is practiced 
to a considerable extent. The heating test, which is in common 
use in Canada, consists of heating a small sample of the milk to be 
tested to 1 20° F. If it will stand this temperature without coag- 
ulating, it is considered to be good milk. If it coagulates when 
heated to this temperature, it is too sour 
to be used for cheese. 

This heating may be considered an 
acid test. When milk contains about 
.3 per cent acid, it usually coagulates 
when heated. It should be borne in 
mind in this connection that different 
samples of milk, containing exactly the 
same amount of acid, do not coagulate at the same tempera- 
ture. Some samples will coagulate upon heating when contain- 
ing a little less than .3 per cent acid, while others will not 
coagulate until more than .3 per cent acid has developed. 

In practice the temperature (120° F.) is not always closely 




Fig. 19. — Trocmner's 15ab 
cock cream-testing scales. 



RECEIVING AND GRADING OF MILK AND CREAM 97 

adhered to. A small portion of the sample to be tested is put 
into a tin cup, and the cup is put into hot water or over a jet of 
steam. When the milk is hot its characteristics are noticed. 

5. Use of Babcock Test and Lactometer. — These tests are 
of special value in detecting watered or skimmed milk. When- 
ever a sample of milk appears watery or blue, it is fair to presume 
that water has been added. The test for specific gravity and the 
test for fat can then be applied to such samples of milk. As a rule 
composite samples are taken daily at creameries, and the patrons 




Fig; 20. — Acid carboy trunnion. 



Fig. 21. — Acid hydrometer. 



paid according to the fat delivered. For this reason water adul- 
teration is not very common at creameries, but is practiced to a 
greater extent in the milk-supplies of cities. The use of the lac- 
tometer in connection with the Babcock test has already been 
referred to under the heading of " Specific Gravity of Milk." 

The Babcock test is now in such general use in America for 
determining the per cent of fat in milk and cream that no other 
will be dealt with here. At one time the Oil-test Churn was used 
quite exclusively for testing cream, but it has gone almost entirely 
out of use. 



98 GRADING AND TESTING MILK AND CREAM 

The Babcock test always deals with weight. For instance, 
when we say that a sample of milk tests 4.0 per cen't or that a 
sample of cream tests 30.0 per cent, we mean that in 100 pounds 
of the milk there are 4 pounds of fat, or in 100 pounds of the 
cream there are 30 pounds of fat. 

For the sake of convenience a sample may be measured into a 
test bottle instead of being weighed, when the accuracy of the 
result is not likely to be affected. Milk may be sampled for the 
Babcock test with a pipette, because the specific gravity of milk is 
always so nearly the same that the same measure of milk from 
widely different sources has, for all practical purposes, the same 
weight, and because milk is in such a liquid condition that it 
neither holds air nor adheres to the wall of the pipette. Rich 
cream, on the other hand, has a lower specific gravity than thin 
cream; moreover, cream is so syrupy or viscous in its nature that 
it will hold air or other gas and stick to the wall of the pipette. 
For these different reasons, the authors wish to state emphat- 
ically, that when cream is tested for commercial purposes, as at a 
creamery, it should never be measured but always weighed into 
the test bottle. The measuring of cream for the Babcock test, 
when this test is made for commercial purposes, is a fraudulent 
practice ; and in most of the States and Provinces of the United 
States and Canada there are laws prohibiting it. 

In taking the sample for a Babcock test of milk a 17.6 c.c. 
pipette is used. This will deliver 18 grams of milk, the quantity 
for which the scale on the test bottle is graduated to read per 
cent of fat. To this we add 17.5 c.c. of sulphuric acid (specific 
gravity i. 82-1 .83), varying the quantity to suit the strength. 
The contents are then thoroughly mixed by giving the bottle a 
rotary motion. The acid acts upon and digests all the solids of 
the milk, excepting the fat, and heats the sample to a desirable 
high temperature. The bottle is then placed in the centrifugal 
tester and whirled for five to six minutes, at a speed suitable 
to the diameter of the machine, usually 8co to 1000 revolutions 
per minute. The bottle is then filled to the bottom of the neck 
with hot water (soft or distilled) and whirled for about two min- 
utes. A second addition of hot water is then made to float the 



RECEIVING AND GRADING OF MILK AND CREAM 99 

fat into the neck to about the 8 per cent mark, after which the 
sample is given a final whirling of one minute. The sample is 
then set in hot water at i30°-i4o° F. to bring it to the right tem- 
perature for reading. A pair of dividers is generally used for 
measuring the fat column in taking the reading. With milk, 
the reading is taken from the highest to the lowest point, that is, 
the meniscus of the fat column is included. 




Fig. 22. Fig. 23. Fig. 24. Fig. 25, 

Skim-milk Whole-milk Cream test- 9-gram cream 

test-bottle. test-bottle. bottle. test-bottle 

Babcock Test-bottles. 




Fig. 26. 
Cream 
test-bottle 



In the Babcock test of cream either a 9- or an 18-gram bottle 
is used. The drift has been decidedly towards the use of the 
bottle graduated to read per cent for 9 grams. A 9-gram sample 
of cream is weighed into the bottle by means of a special cream 
scale. To this are added about 9 c.c. of commercial sulphuric 
acid, and the contents are mixed by giving the bottle a rotary 
motion. When the action of the acid has proceeded far enough — 



100 GRADING AND TESTING MILK AND CREAM 

when the contents have reached a chocolate color — some hot 
water is added to the test bottle to check the action of the acid. 
The sample is then centrifuged for five to six minutes, after which 
hot water is added to float the fat into the neck of the bottle; 
then the sample is again whirled for two minutes. The reading 
is taken at a temperature of i3o°-i4o° F., after a few drops of a 
colored reader, composed of a light mineral oil with suitable 
coloring matter in it, have been added to flatten the meniscus. 
Dividers are used for measuring the fat column in taking the 
reading. 

There are three very common conditions which make it dif- 
ficult to obtain a fat reading: (i) Black, charred, flocculent 
matter is sometimes found at the bottom of the fat column. This 
is commonly caused by using too much or too strong acid or by 
mixing milk and acid at too high a temperature. The remedy 
is to use less acid or to cool milk and acid before mixing. The 
black charred matter may also be due to allowing the acid to 
stand in contact with the milk too long a time before mixing or to 
pouring acid through the center of the milk. (2) There may be a 
layer of white flocculent matter at the bottom of the fat column. 
In this case an insufficient quantity of acid may have been used, 
the temperature of the milk and acid may be too low, or they 
may not have been thoroughly mixed. The remedy is to use 
more acid, to warm milk and acid before mixing, or to shake the 
mixture thoroughly before whirhng. (3) Occasionally there is a 
layer of impure foam at the top of the fat column. This is gen- 
erally due to the use of hard and impure water. The remedy is to 
use pure distilled hot water. For more detailed information on 
this subject see " Testing Milk and its Products," by Farrington 
and Woll. 

Does the Babcock Test, as Ordinarily Applied to Cream, Give 
too High a Reading? — An investigation made by Harry B. Sieg- 
mund, Analyst, Hendler Creamery Company, and R. Sewell 
Craig, Senior Food Chemist, City Health Department, Balti- 
more, resulted in a decision that the Babcock test of cream, as 
ordinarily conducted, gives too high a reading. The following is 
a brief summary of the results obtained : 



BABCOCK TEST OF BUTTERMILK AND SKIM-MILK 101 

When the centrifuging was done in a thirty-six bottle, elec- 
trically driven machine, run at a speed of looo revolutions per 
minute, the average of the tests of a number of samples of cream 
was I .o per cent higher than that obtained by gravimetric analy- 
sis (Rose- Gottlieb test); and where the test was made with a 
twenty-four bottle steam-turbine machine, run at a speed of 800 
revolutions per minute, the average test was 1.5 per cent too 
high. 

With the electrically driven machine run at a speed of 1200 
revolutions per minute the reading was 0.6 per cent higher than 
that obtained by the Rose-Gottlieb test. 

When an electrically driven machine, run at a speed of 1600 
revolutions per minute, was used, the Babcock test and the Rose- 
Gottlieb test gave practically the same results. 

The conclusion was that with machines run at the lower 
speeds a little water, or water and acid, remains suspended in the 
fat, and that it requires the force created by the higher speed 
machine completely to separate this from the fat. 

Babcock Test of Buttermilk and Skim-milk — The American 
Association Test. — In an exhaustive investigation of the losses 
of fat in buttermilk, conducted by Professor J. W. Mitchell 
under the direction of the senior author and not yet completed, 
several points have come prominently to the fore. 

The first of these is that the losses of fat in buttermilk, in 
our creameries, are much greater than they are generally sup- 
posed to be. Many creameries, under their methods of testing, 
are getting tests of .1 per cent to .2 per cent fat for their butter- 
milk. Of between 250 and 300 complete records, made by 
Professor Mitchell and the author, of churnings at dififerent 
creameries, not one showed a Babcock test as low as .2 per cent. 
Of course the test was rigorous, but even this was considerably 
below the chemical analysis. 

The second point is that there are a large number of factors 
which influence the per cent of fat in the buttermilk, such as 
length of time taken to churn, temperature of cream, length of 
time the cream is held at churning temperature, condition of 
cream, fullness of churn, speed of churn, etc. This means that 



102 GRADING AND TESTING MILK AND CREAM 

every creamery has its own conditions and problems to meet, and 
consequently should be in a position to determine, readily and 
accurately, what its losses of fat in the buttermilk are. It will 
then be in a position to study how to reduce them. 

The third point is that the average creamery, under its 
methods of testing, is not aware of what its losses are. It is not 
uncommon to note, in creamery records, tests of .i per cent to 
.2 per cent for the buttermilk, whereas it is known, from hun- 
dreds of analyses made in the laboratory of the American Asso- 
ciation of Creamery Butter Manufacturers, that the average 
loss exceeds .5 per cent fat. The loss does not fall far short of a 
pound of butter to every hundred pounds of buttermilk. 

Realizing the necessity for a simple test that would corre- 
spond closely with chemical analysis for buttermilk (or skim- 
milk) , and that could be operated by anyone capable of conduct- 
ing a Babcock test, the senior author asked Professor Mitchell to 
devise such a test, if possible. In his efforts he has fortunately 
been very successful. 

The different methods of making a Babcock test of butter- 
milk, including the new modification of the skme, are briefly out- 
lined below. 

The following method of testing buttermilk (or skim-milk) 
has been in use for many years, and is still more generally used 
than any other. A double-necked skim-milk bottle, graduated 
to read as close as .01 per cent for 18 grains, is used. Most of 
the bottles read up to .25 per cent — some to .50 per cent. After 
the buttermilk is well mixed, a 17.6 c.c. pipette is used to transfer 
18 grams of it to the test bottle. To this is added 20 c.c. of 
commercial sulphuric acid (sp. gr. 1.82-1.83). The acid and milk 
are then thoroughly mixed by giving the bottle a gentle, rotary 
motion. Care must be exercised, in mixing, to avoid choking 
the small neck and causing some of the contents to be thrown 
out through the large neck. The bottle is then placed in the 
centrifuge and whirled at full speed for about five minutes. 
Hot water (soft or distilled) is then added to the bottle to fill it 
almost to the neck and the machine is again run for one or two 
minutes. Hot water is then added to float the fat into the small 



AMERICAN ASSOCIATION TEST 103 

neck and the bottle is again whirled for one or two minutes. 
The bottle is then placed in hot water at a temperature of 130°- 
140° F., after which the reading is taken. It is advisable to use a 
pair of dividers to measure the fat column. Under this method 
the reading will be very low — possibly .1 per cent to .2 per cent 
when it should be .4 or .5 per cent. 

A More Rigorous Test. — A modification of the foregoing is to 
take a 9-gram sample by means of a 9 c.c. pipette, that is, a 
half sample. To this is added about 1 2 c.c. of a fairly strong acid, 
well up to a sp. gr. of 1.83. The whirling is done in a very high- 
speed machine and is greatly prolonged — fifteen to twenty min- 
utes the first time, about ten minutes at the second whirling, and 
about five minutes at the third whirling, or thirty to thirty-five 
minutes in all. The reading must be doubled, since only a 9-gram 
or half sample is taken to a test. This method will probably 
double, or more than double, the result. But even under 
this method the test falls considerably below the results secured 
by chemical analysis. 

The American Association Test.— A close study of the dif- 
ferent practical methods for the quick determination of the per 
cent of fat in milk and its products and by-products reveals 
the fact that there is a general principle running through them 
all, that is, there are three factors which operate in all of them. 
These are (i) the use of one or more chemicals to liberate the 
fat, (2) the heating of the contents of the test bottle in order 
to liquefy the fat, and (3) the application of centrifugal force. 
Where sulphuric acid is the chief or only chemical used it gen- 
erates sufficient heat, through its strong affinity for water; but 
where it is not used at all or is used very sparingly it becomes 
necessary to heat the sample in hot water before centrifuging it. 

A number of useful tests have been devised for the quick 
determination of the per cent of fat in milk, etc. The following 
are a few of the most outstanding of these: 

(i) The Lactocrite, devised in 1886 by Dr. De Laval, inventor 
of the cream separator which bears his name. The chemical 
used was concentrated or glacial acetic acid, containing 5 per 
cent of concentrated sulphuric acid. It was necessary to heat 



104 GRADING AND TESTING MILK AND CREAM 

the sample before centrifuging it. This was a pioneer test but is 
not now in use. 

(2) The Babcock test, invented by Dr. Babcock of the Wis- 
consin Experiment Station and pubhshed in July, 1890. This 
test is so \yidely and favorably known and is in such general 
use, especially in America, that it seems unnecessary to do more 
than refer to it. It is simple, speedy and accurate, and the cost 
of a test is small, a single, cheap chemical, commercial sulphuric 
acid, being used. 

(3) The Gerber test, brought out in 1892. In this test two 
chemicals are used, viz., commercial sulphuric acid and amyl 
alcohol. It is used quite extensively in Europe. 

(4) The Sinacid Butyrometer. This test was devised by 
Sichler of Germany in 1904. No acid is used in the test, hence 
the name " Sinacid." The chemicals used are sodium hydrox- 
ide, Rochelle salt and iso-butyl alcohol. It is necessary to heat 
the samples by placing them in hot water before centrifuging 
them. 

All of these tests were designed primarily for the testing of 
milk and such milk products as cream, and for this purpose 
they are reliable; but in testing the by-products of the dairy, 
skim-milk and buttermilk, they all give results that fall con- 
siderably below those obtained by chemical analysis (the Rose- 
Gottlieb test). No doubt this is the main reason for the failure 
there has been to make a thorough study of the losses of fat in 
buttermilk and how to overcome them. Hence, when the 
American Association of Creamery Butter Manufacturers began 
its study of losses of fat in buttermilk it was confronted with 
the problem of devising a suitable test for the accurate deter- 
mination of the per cent of fat in buttermilk. 

Trials were made of different combinations of chemicals, 
such as, sulphuric acid and amyl alcohol, sulphuric acid and iso- 
butyl alcohol, and sulphuric acid and normal butyl (w-butyl) 
alcohol. After extensive experiments had been made sulphuric 
acid and w-butyl alcohol were selected as the most suitable 
combination to use, and for the following reasons: 

(i) The results, with duplicate tests, are exceptionally uni- 



AMERICAN ASSOCIATION TEST 105 

form and correspond closely to chemical analysis (The Rose- 
Gottlieb test), as the accompanying table shows. 

(2) There is much less trouble with a deposit in the test 
bottles than is the case where the other alcohols are used. 

(3) Normal butyl (w-butyl) alcohol, being a single alcohol 
that is readily purified, is free of impurities while the amyl and 
iso-butyl alcohols are not likely to be. In blank tests made, 
that is, when water was substituted for buttermilk in a test, a 
short column of some impurity rose into the neck of the test 
bottle when the amyl and iso-butyl alcohols were used, but not 
when w-butyl alcohol was used. 

(4) The w-buty] alcohol is quite stable and is not at all likely 
to be attacked by the sulphuric acid, while the other alcohols 
mentioned are iso-alcohols that run off into chains and are less 
stable and are likely to be mixtures. 

(5) The w-butyl alcohol does not possess either a pungent or 
an otherwise offensive flavor or odor, and consequently is much 
pleasanter to use than the others. 

(6) The w-butyl alcohol is the lowest in price of the dif- 
ferent alcohols, and, being stable and free of impurities, is the 
most reliable alcohol to use. Even the cheaper grade of this 
alcohol (the " practical ") contains no impurity excepting pos- 
sibly a slight amount of moisture. 

Extensive and carefully conducted investigations have 
shown that the right amounts of commercial sulphuric acid 
and w-butyl alcohol to use in testing a 9-gram sample of 
skim-milk or butter-milk are as given in the directions which 
follow : 

Directions for making a test : 

Chemicals. — Commercial sulphuric acid. 
Normal butyl alcohol. 

I. Place the chemicals and buttermilk in the test bottle in 
the following amounts and the order indicated. 

(a) 2 c.c. of w-butyl alcohol. 

(b) 9 c.c. of buttermilk. 

(c) 7 to 9 c.c. of commercial sulphuric acid. 

Vary amount of acid to suit its strength. The right amount 



106 



GRADING AND TESTING MILK AND CREAM 



is being used when the fat column is golden yellow to light amber 
in color. 

2. MLx contents of bottle thoroughly. 

3. Centrifuge for six minutes. 

4. Add hot water (soft or distilled) to fill bottle to bottom 
of neck, and whirl for two minutes. 

5. Add balance of water to float fat into neck and again whirl 
for two minutes. 

6. Read at temperature of 130" to 140° F. Double the read- 
ing to obtain per cent of fat. 

7. In cleaning test bottle — especially if there be any deposit — 
first add a small amount of lukewarm water and to this add 
sulphuric acid. Always add the water first and then the acid — 
never the reverse. Rinse the bottle well with this mixture and 
then rinse with hot water. 

This test gives results corresponding to those of chemical 
analysis. 

A test bottle, with a scale reading up to .50 per cent for 18 
grams, should be used. 

The following table, comparing the Babcock, The American 
Association Test, and Rose-Gottlieb (Chemical) tests, is sub- 
mitted. 



Babcock Test ^ 


The American 


Rose-Gottlieb 




Association Test 


Test 


Per Cent 


Per Cent 


Per Cent 


■38 


■52 


■52 




34 




47 




47 




40 




57 




59 




43 




60 




60 




36 




54 




53 




39 




S6 • 




59 




36 




50 




52 




34 




5° 




48 



^ The Babcock test given in the foregoing table was that obtained from using 
12 c.c. of sulphuric acid with a 9-gram sample and centrifuging, in all, about 
thirty-five .ninutes in a high-speed tester. 



PER CENT OF FAT IN BUTTER 107 

Determination of the Per Cent of Fat in Butter. — The methods 
for the determination of the per cent of fat in butter may be 
classified under two heads, viz., 
(i) Scientific methods, such as 
{a) The Extraction method. 
(5) Rose-GottHeb method. 
(c) Indirect determination of fat. 
(2) Practical methods, such as 

(a) The 90 per cent bottle designed by Hepburn for use 
in the Babcock test. 

(b) The Shaw test. 

Scientific Methods. — The scientific methods are too com- 
plicated and require too long a time for their completion to be of 
practical use in a creamery. 

The Rose-Gottlieb method may be briefly outlined as follows: 

This method, which was originally designed for the estima- 
tion of fat in milk, can be used with advantage also for the deter- 
mination of fat in butter. 

According to A. Hesse,^ about 2 grams of butter are weighed 
out into a 3 cm. long, half-cylindrical glass tube, or simply 
wrapped in a piece of stiff fat-free paper of the same form. The 
tube or paper and the contained fat are then introduced into a 
Gottlieb cylinder, and hot water is added until the lo-cm. mark 
is reached. If the butter does not melt, the cylinder is placed in 
warm water until it does. Then i c.c. of ammonia and 10 c.c. 
of 95 per cent alcohol are added, exactly as in the estimation of 
milk-fat. If the mixture is still warm, the cylinder is cooled in 
cold water so that the ether which is to be added will not evap- 
orate too quickly. The cooling must not, however, be carried 
too far; otherwise the butter will become solid again. Twenty- 
five c.c. of ether are then added, and the contents of the cylinder 
mixed by repeatedly inverting it. Afterwards 25 c.c. of petro- 
leum ether are added and the mixing repeated. 

After the different layers have separated quite sharply from 
one another, the clear ether-fat solution is siphoned off in the 
usual way, the lower opaque layer not being disturbed. Then 

1 Molkerei-Zeitung, Hildesheim, 1903, No. 27. 



108 GRADING AND TESTING MILK AND CREAM 

50 c.c. of ether are poured into the cyhnder and at once siphoned 
off without being mixed with the other Kquid. Finally, the 
residual liquid is shaken with a mixture of 25 c.c. ether and 25 c.c. 
petroleum ether, and, after setthng, the ethereal layer is drawn 
off. The three portions of ether are naturally all placed in 
the same tared flask, which is weighed again after the ether has 
been evaporated and the fat dried. 

These repeated extractions with ether and petroleum ether 
are necessary if exact results are to be obtained. If the above 
directions are carefully followed, it will be found that the Rose- 
Gottheb method, while easier and more convenient, and also 
considerably quicker than the extraction method, gives results 
which are in very close agreement with those obtained by the 
latter. 

The Mojonnier test is a modification of the foregoing, and 
possesses several features which greatly facihtate the work and 
shorten the time required to make the test. In the method 
known as the " Indirect Determination of Fat," the percentages 
of moisture, casein and salt are carefully determined. These 
are then added together and their total is subtracted from 100 to 
determine the per cent of fat in the butter. 

Practical Methods. — There are several practical methods that 
are made use of to a greater or less extent. We shall briefly 
outline two of these. 

For making a Babcock test of butter, using the Ilhnois 9-inch, 
9-gram, 90 per cent butter test bottle devised by Dr. N. W. 
Hepburn, University of Illinois, the following directions are given: 

" Taking the Sample. — In testing butter it is necessary to 
exercise great care both in securing and in preparing the sample. 

" Sampling from a Churn. — With an ordinary ladle cut off 
the surface of the butter in several places, including each end and 
the middle of the churn. Then make a composite sample by 
taking, with a spatula or common case knife, a small sample 
(10 to 20 grams each) from six or eight different places in the 
churn where the surface has been removed, putting them into 
an 8-ounce wide-mouthed glass-stoppered bottle. 



PER CENT OF FAT IN BUTTER 



109 



" Sampling from a Tub. — Draw one or two triers from the 
full depth of the tub and drop the entire plug of butter into the 
glass-stoppered bottle. 

" Preparing the Sample for Testing. — Place the glass-stoppered 
bottle containing the sample in warm water, shaking vigorously 
every few seconds until it is thoroughly mixed and is about the 
consistency of heavy cream, when it is ready to be weighed into 

test bottle. Caution. — Be careful not to get ^ ^_ ^ 

the sample too warm nor in too liquid a condi- 
tion. If this happens place it in cold water, 
shaking very frequently, until the sample takes 
on the desired consistency. Samples should not 
pour freely, but like thick cream or paste. Little 
heating and thorough shaking is the rule for suc- 
cess in preparing the sample. 

" Weighing the Sample. — Balance the bottle 
on the scales and weigh out a 9-gram sample by 
the method used in weighing cream samples. 
(Scales as sensitive as moisture-test scales 
should be used.) 

" Adding Acid. — First add about 9 c.c. of 
water then 17.5 c.c. of sulphuric acid. Caution. 
— Add the acid slowly and in small portions, 
shaking after adding each portion to avoid 
foaming. High-salt samples are most likely to 
foam. If foaming occurs, vigorous shaking will 
often prevent the loss of the sample. After the 
sample is thoroughly mixed with the acid and is 
dark brown in color, add warm water, fiUing the 
test bottle up to the base of the neck. 

" Whirling. — Place the test bottles in the 
tester and whirl for ten minutes; stop, fill with 
water to bring the fat up in the graduated neck, 
and whirl again for five minutes. 

" Reading. — Set the test bottle in water at 
140° F., covering the fat in the neck, and 
allow it to stand for at least five minutes; then read. In read- 



FiG. 27. — Illinois 
9 inch, 9 gram, 
90 per cent 
butter test 
bottle. 



no 



GRADING AND TESTING MILK AND CREAM 



ing, cut ojff all the upper curve on the fat column or add a 
couple of drops of white mineral oil (glymol) to destroy the 
meniscus." 

THE SHAW TEST FOR FAT IN BUTTER 

APPARATUS REQUIRED 

" Babcock centrifuge or tester.^ 
Shaw separatory funnels. 

" Balance which is sensitive to o.oi gram. (A torsion bal- 
ance, such as is used in testing for moisture, will answer if it is 
in good condition.) 

" Accurate set of metric weights. 




Fig. 28 — Separatory funnels used in the Shaw test. 

" Glass cylinder graduated at 9 and 11 c.c. 

loo-c.c. glass beaker. 
" Wooden rack for holding separatory funnels. 

Support for separatory funnels on balance. 
" In addition to the above a special socket to hold the separa- 
tory funnels will be required. As shown in the cut, this differs 
in no material way from the socket ordinarily used in the Bab- 

iL. F. Nafis. 



PER CENT OF FAT IN BUTTER 111 

cock centrifuge, except for the opening in the side. It may 
easily be adapted from the ordinary socket or if preferred the 
socket may be sent to us and we will make the necessary changes 
for a nominal charge. Care must be taken that the capillary 
stem of the funnel does not project far enough through the hole 
in the socket to strike against the side of the centrifuge while 
being whirled. It is a good plan to fit a disk of rubber gasketing 
in the bottom of the socket. 

SAMPLING THE BUTTER 

" In the determination of fat in butter, great care must be 
taken in securing a representative sample and in preparing this 
for the test. 

" Several samples from different parts of the tub or churn 
should be taken with a butter trier. These are placed in a suit- 
able container, such as a i-pint Mason preserve jar or a cup, 
which is placed in water at about ioo° F. The sample is then 
mixed with a spatula or spoon until about the consistency of 
thick cream. The sample must not be left any length of time in 
open containers, since some of the moisture will evaporate. 
Should the sample be kept for any reason for a day or two 
before it is mixed, it should then be placed in warm water (with 
the cover on the container) until melted, and then cooled while 
being vigorously shaken until it soHdifies. The reason for this is 
that on standing some of the water will ooze out and cannot be 
reincorporated except by emulsifying and cooling while in this 
condition. Too much stress cannot be laid on careful sampling 
and mixing the sample, for upon this the accuracy of any deter- 
mination in butter very largely rests. 

DETERMINING THE FAT 

" It will be found more economical in some cases if four or 
multiples of four determinations are made at once. In this case 
the two double sockets containing the funnels will balance when 
placed opposite in the centrifuge. If but one or two determina- 
tions are to be made it will be necessary to balance the centrifuge 
by putting weights in the opposite socket. First of all, the clean 



112 GRADING AND TESTING MILK AND CREAM 

and dry separatory funnel must be weighed, and this as well as the 
other weighings involved must be done with care. This weight 
once found will suffice for all determinations made with that par- 
ticular funnel, unless by accident some of the glass should be 
chipped off. A slight scratch made with a file can serve to iden- 
tify the funnels. A paper label should not be used. If requested 
at the time of ordering we will number them without additional 
charge. 

" Each time, before using the separatory funnels, they should 
be lubricated with a properly prepared stopcock lubricant which 
we supply with directions for its use. 

" I. Weighing the Charge. — Counterpoise the small beaker 
on the balance and carefully weigh out 20 grams of the sample 
mixed as directed. 

" II. Transferring the Charge to the Separatory Funnel. — 
Place the beaker containing the charge on a radiator or steam 
pipe until the butter is melted. (This may also be accom- 
plished by adding a small quantity of boiling water.) Next 
pour the charge into the funnel kept in an upright position in the 
wooden rack. No part of the charge must be lost in transferring. 
With a fine stream of hot water rinse down the sides of the 
beaker and pour the rinsings into the funnel. (If the salt is to 
be determined, distilled water must be used. See directions 
under ' Salt Test.') Repeat this, using not more than a tea- 
spoonful of water at a time until the funnel is full to within 
about one-quarter of an inch of the shoulder. The rinsing can 
be done very conveniently with the arrangement on many steam 
centrifuges for filling the Babcock test bottles, i.e., the rubber 
tube ending in a glass or metal point and connecting with a water 
tank heated by steam. The point must be fine, however. Should 
it be larger than three-sixteenths of an inch, it can be replaced 
with the tip of a small oil can. Should this arrangement not be 
at hand, one can easily be improvised from a tin can, a rubber 
tube, and an oil-can tip. In transferring the melted butter 
and rinsings, the last drop may be prevented from running down 
the outside of the beaker by touching the lip of the beaker to the 
neck of the separatory funnel. 



PER CENT OF FAT IN BUTTER 113 

" III. Centrifuging. — Insert the separatory funnel in the 
special socket, allowing the stem to project through the hole in 
the bottom and the handle of the stopcock through the open side. 
Caution. — The socket must always be placed in the centrifuge, 
with the open side facing the direction in which the wheel revolves. 
This is very important, if the opening faces the reverse direction 
the stopcock will be thrown out and broken. Whirl one minute 
at the same speed used in testing milk with the Babcock test. 
The centrifuge must be kept warm. 

" IV. Removing the Water. — Remove the separatory funnel 
from the socket and allow the water to flow through the stopcock 
until the fat (or curd) is within one-eighth of an inch of the stop- 
cock. In this and later operations involving the stopcock one 
must be sure it does not stick. It must always be under control, 
and it is best to give it frequent slight movements when the water 
or acid is running through it to be sure that this control is main- 
tained; otherwise it might stick at a critical moment and the 
determination be lost. The most of the salt and part of the curd 
are taken out by the water. The remainder of the curd and all 
of the fat stays in the funnel. If it is desired to determine the 
salt, this wash water is allowed to run into a 250 c.c. flask and the 
operation described in this paragraph conducted three times 
instead of but once, the wash water being added each time to 
the flask. 

" It sometimes happens that the water will not start flowing 
when the stopcock is opened, in which case it can be started by 
blowing into the mouth of the separatory funnel. 

" V. Dissolving the Curd. — Measure out 9 c.c. of cold water, 
preferably condensed steam, with the glass graduate and pour 
into the beaker. Add to this 11 c.c. of sulphuric acid of the same 
strength used in testing milk and cream (specific gravity, 1.82- 
1.83) and mix by gently shaking. (Caution. — Always add acid 
to water and not water to acid, or a serious accident may result.) 
While still very hot add the mixture to the contents of the separa- 
tory funnel. Now dissolve the curd by giving the funnel a 
circular motion with the hand grasping the neck. Centrifuge 
one minute, as before. Draw off the acid solution till the fat 



114 GRADING AND TESTING MILK AND CREAM 

layer is within about one-fourth of an inch of the stopcock and 
repeat the operations in this paragraph. 

" VI. Freeing the Fat from the Acid Solution. — The fat will 
now be in a clear transparent layer free from curd, and the solu- 
tion below it will be practically colorless. To separate these two 
draw off the latter until the fat nearly reaches the stopcock and 
centrifuge another minute. Now allow the fat to come down 
through the stopcock till it just reaches the end of the capillary 
stem. This last step offers no difficulties, providing the stopcock 
is kept in control, but it requires care. If desired, the acid may 
be colored with methyl orange. 

" VII. Determining the Percentage of Fat. — Carefully dry 
the separatory funnel on the outside with a clean soft cloth and 
weigh it. The weight thus obtained manus Ihe weight of the 
empty funnel represents the weight of butter-fat in 20 grams of 
the sample. The percentage is obtained by multiplying by 5. 

" Often it is possible to obtain a clear fat layer with but one 
addition of acid, but in some cases it will be found necessary to 
add it the second time, as directed. The test for fat alone 
involves 4 centrifugings of one minute each. The centrifuge 
should be kept warm and the contents of the funnel in a melted 
state when the acid is added. The time consumed should not be 
longer than it takes to test cream with the Babcock test, and the 
operations involved are simple and easily learned. No difficulty 
will be experienced in obtaining a clear fat. Occasionally there 
will appear a slight emulsion at the bottom of the fat layers 
when the fat is drawn into the stem. This is so small in amount 
that it does not seem to affect the accuracy of the test to any 
considerable extent. The emulsion should be weighed as fat and 
considered as such. 

CLEANING THE SEPARATORY FUNNELS 

" The separatory funnels should be washed after each deter- 
mination, but it is not necessary to dry them before use, providing 
their weight, when clean and dry, has been found. The cleaning is 
easily done with hot water and either soap or cleansing powder. 
They should be well rinsed off with clean water and drained." 



GRADING AND TESTING MILK AND CREAM 115 




Fig. 29.-— Churn room. Kirschbraun & Son, Omaha, Neb. One of the largest 
and finest creameries in the world. 




Fig. 30. — Street view of the first prize co-operati\'e creamery at Carroll, Iowa. 



116 



GRADING AND TESTING MILK AND CREAM 



Very few of the creameries have, as yet, begun the regular 
determination of the per cent of fat in their butter, most of them 
confining their work on the composition of butter to determina- 
tions of the per cent of moisture and the per cent of salt. The 
three constituents of butter outside the fat, are moisture, salt 
and curd ; and where a uniform system of manufacture is adopted, 
and the churning is done under right conditions and the butter 
well washed, the curd content is not Hkely to exceed i per cent 




Fig. 31. — The oil- test churn. 



or vary more than half a per cent. Consequently accurate 
determination of the moisture and salt-contents enables a 
creamery to estimate, very closely, the per cent of fat in the 
butter. 

Sediment Test. — Milk should be free from sediment and 
foreign insoluble material. Producers of the raw material are 
not always conscious of the necessity of producing clean milk, 
and of the effects of impurities upon the finished products. 

Sediments may be seen on the bottom of a glass jar after the 



NECESSITY OF GOOD MILK 



117 



milk has stood quietly for several hours. The better way of 
showing these sediments is to use the Wisconsin Sedimentation 
Test. The container for this test holds about one pint of milk. 
A screw cap fits over the top. By means of a small air pump, 
pressure can be applied and the milk forced through a disk or 
filter. This disk is removable and the filtered-out dirt on the 
surface can thus be shown. 

Necessity of Good Milk. — All authorities agree that the best 
grade of butter and cheese cannot be made from sour or tainted 
milk. The two countries renowned for the excellence of their 





Fig. 32. — Wizard tester. Fig. 33. — Twentieth-century hand tester. 



dairy products — Denmark and Canada — owe their success 
largely to the purity of the milk from which these products are 
made. Makers who have won for themselves national reputa- 
tions in cheese- and butter-making have almost invariably been 
men who insisted on getting first-class milk. The method of 
classifying milk and cream and paying for each according to 
qudhty has been adopted by some creameries. 

The authors do not hesitate to say that cream whose flavor 
is such as to show that it is in a putiefactive or decomposed 
condition should be rejected as unfit for making an article of 
hcman food. While it is advocated by some that it should be 



118 GRADING AND TESTING MILK AND CREAM 

received, made into butter and sold on its merits, the wisdom 
of this is to be questioned. Cream that is simply off in flavor is a 
different proposition. This may, in justice and fairness, be 
taken in on its merits and paid for accordingly. The practice 
of receiving and paying for cream indiscriminately is something 
which should be condemned and discouraged. The authors have 
come in contact with many patrons in different parts of the 
country and have yet to meet the first patron who would seri- 
ously object to taking his milk or cream home when thoroughly 
convinced that its condition was such that it should not be 
received. Patrons, as a rule, respect the maker who keeps his 
creamery in a good sanitary condition and insists upon being 
suppHed with a good quality of milk or cream. It should be the 
aim of every creameryman to make the highest grade of butter 
possible, and thus be in a position to take full advantage of a dis- 
criminating market, for this is the kind of market that pays the 
highest prices. 

Sampling of Milk.^ — The sampling of milk and cream for fat 
tests is one of the most delicate problems with which the creamery 
operator has to deal. If a proper sample is not obtained, the 
ultimate test will not be correct, no matter how carefully the 
succeeding steps may be carried out. There are two methods of 
sampHng in use: First, sampling with a small dipper, and 
second, sampHng with a sample-tube, or milk- thief. The 
sampling of milk for composite samples should be done every 
day, and the samples taken should represent the average quality 
and form a certain proportionate part of the milk or cream 
delivered. 

In order to get a sample which represents the average quaHty, 
the milk or cream delivered must be thoroughly stirred, so as 
to get an even distribution of the fat. 

In order to get a proportionate part of the milk or cream 
delivered from day to day, it is necessary to use a samphng- 
tube. 

The sampling of milk and cream with a dipper for composite 
samples has been in use for a long time, and is still practiced to 
quite an extent. However, it is fast becoming recognized that 



SAMPLING OF MILK 119 

the use of a suitable sampling tube is much better. It takes a 
more representative sample of a can of cream, whether it be for 
the making up of a composite sample or for the testing of an 
individual shipment. In the case of composite samples of both 
milk and cream it takes an aliquot portion, or one in proportion 
to the quantity of milk or cream delivered. The difficulty at 
one time in sampling cream — and particularly thick cream — 
with the sampling tube was that the only opening in the tube 
was at the bottom, and the cream would not flow into it as the 
tube was lowered. However, this trouble is completely over- 
come when a sampler like the McKay sampler is used. This is 
made up of two tubes, an inner and an outer, and a plunger 
(see cut). Both the tubes have openings up the side. Before 
inserting the sampler in a can of cream, the outer tube is turned 
on the inner so that the openings are not opposite each other, or 
so as to close the sampler, and the plunger is drawn back. The 
sampler is then lowered into the cream to the bottom of the can, 
when it is opened momentarily to allow it to fill and is then closed 
again. In empt3dng the sampler the outer tube, which is the 
shorter of the two, is drawn up a Httle to leave an opening at the 
bottom, and the plunger is pushed down to force the cream out of 
the tube. In doing so it cleans the tube completely. This style 
of sampler does equally efficient work whether used in a 
creamery or cream station, or in taking samples on a cream 
route. 

An investigation made by the American Association of Cream- 
ery Butter Manufacturers showed the dipper method of sampKng 
cream to be unreHable. In this investigation the cream in the 
can was first hand-stirred — no less than forty vigorous double 
strokes being used — and then sampled with a dipper, after 
which a sample was taken by means of a McKay or tube sampler. 
In all, thirty-two lots of cream were sampled and tested in this 
way, and the following short table gives some of the results 
secured: 



120 



GRADING AND TESTING MILK AND CRI:A.M 



Sample 


Times 


No. 


Stirred 


I 


5° 


2 


40 


3 


65 


4 


60 


5 


44 


6 


60 


7 


75 


8 


50 



Condition of Cream 



Viscous, not very smooth . . 

Smooth and even 

Heavy on top, Hquid below, lumpy 
Viscous but good condition. 

Quite liquid 

Viscous, slightly lumpy .... 
Top fair, bottom almost solid, 

lumpy 

Good condition 



Babcock Test of 


Dipper 


Tube 


Sample 


Sample 


41 .0 


44.0 


39 -o 


39-5 


42.5 


38.5 


34-5 


33 -S 


26.5 


24-S 


40.5 


40.5 


47 -S 


38.5 


40-5 


39-S 



Difference 



Per Cent 
30 
o-S 
4.0 
i.o 
2.0 
0.0 

9.0 
1.0 



While the difference in the test of the samples under the two 
methods was usually not great, yet the dipper method of sampling 
proved unreliable. 

Sampling-tube. — At creameries where milk is received, the 
sampling- tube, or milk- thief, gives the best results and satis- 
faction. It is very difficult in practice to get a proportionate 
sample with a dipper, from day to day. To illustrate : A patron 
who delivers 200 pounds of milk testing 3 per cent fat one day 
may on another day deliver 100 pounds of milk testing 5 per cent 
fat. If a dipperful is taken from each for a composite sample, the 
test of that composite sample will be 3 + 5-^2, or 4 per cent. 
According to this test, these 300 pounds of milk delivered will 
contain 12 pounds of butter-fat. In reality 6 pounds of fat were 
dehvered in the 200 pounds, and 5 pounds of fat in the 100 pounds, 
making a total of 11 pounds of fat. Thus we see that the dipper 
method is not reliable, and in this case the patron was paid for 
I pound of butter-fat too much for the two days' delivery. If 
the sample taken from the 200 pounds of milk had been twice as 
great as that taken from the 100 pounds of milk, then the com- 
posite test would have been perfect, no matter whether it had 
been taken with a dipper or with a sampling- tube. If the same 
weighing-can is used every day, it is possible to maintain an 



SAMPLING TUBE 



121 




Fig. 34. — \'at room. Kirschbraun & Son, Omaha, Neb. One of the largest 
and finest creameries in the world. 




Ftg. 35. — Interior of creamery, Strawberry Point, Iowa. One of the largest 
whole-milk creameries in the U. S. 



122 



GRADING AND TESTING MILK AND CREAM 



exact proportion for a sample by always putting the sampling- 
tube perpendicularly into the milk at the same place in the weigh- 
ing-can, and by exercising care in other respects. 

When the cream is being collected from different patrons 
by a hauler, a milk- thief often works unsatisfactorily. This is 
especially true during cold weather. A cream tube similar to 
the one shown in the accompanying illustration is more effective. 



^^ C5s=«; 



^ 


= 


=!7 


c 


P 






-90 


10- 




-80 
-70 


30- 




-CO 

-50 


20- 




-40 
-30 


10- 




-20 
-10 


c^ 




~~> 



Fig. 36.- 



-The McKay cream and 
milk sampler. 



Fig. 37. — Cream 
sampling-tube. 



The way in which the tube is used is apparent from the figure. 
If a certain patron has 40 pounds of cream, the cream is filled 
to the 40 mark on the scale of the tube; if he has 30 pounds, it is 
filled to the 30 mark, etc. 

Sampling Churned Milk. — It occasionally happens that the 
milk arrives at the creamery slightly churned. This is espe- 
cially the case during the summer. Usually such milk is sam- 
pled in this condition, but if it is desired to find the percentage of 
fat in such milk in its unchurned condition, it is essential to melt 



SOUR AND COAGULATED MILK 123 

the churned fat before sampling. If the butter has been churned 
into a few large lumps, these lumps can be taken out in a pan, or 
pail, with a comparatively small amount of milk, and this 
heated until the butter has melted. This is then remixed with the 
milk from which it was first taken and sampled while it is being 
stirred. 

The churning of the milk during transit is mainly due to 
two things: First, to a high temperature of the milk (65° to 
85° F.) and second, to hauHng partly filled cans a long distance 
over rough roads. If the temperature of the milk is low (about 
50° F.), when it leaves the producer, there is seldom any danger 
of having churned milk at the creamery. 

Frozen Milk. — ^When milk is cooled to 31° F., or below, it 
freezes. Ice forms near the sides and bottom of the can, until 
a funnel-shaped cavity filled with milk is left in the center. 
According to both Richmond and Fleischmann, the icy por- 
tion contains more water than the unfrozen milk, and the 
unfrozen portion is rich in solids. According to Farrington, 
when 25 per cent of the sample of milk was frozen, the icy 
portion contained about i per cent less fat than the original 
portion. When about half of it was frozen there was no great 
difference in the fat-content of the frozen and unfrozen parts. 

In practice, however, freezing seems to have a different effect. 
When a can full of partly frozen milk is sampled at the creamery, 
the unfrozen milk nearly always contains less fat than the original 
sample. This can be accounted for by opening the can of milk 
and noting the amount of frozen cream on the sides near the top. 
Whether the unfrozen portion contains less or more fat than the 
original depends, therefore, upon conditions. At any rate, 
frozen milk has a composition different from that of the original 
sample. On this account an accurate sample cannot be had, 
unless the frozen portion be first completely melted and well 
mixed with the remainder. 

Sour and Coagulated Milk. — In order to get a fair sample 
from a can of sour and coagulated milk, it must be stirred 
very thoroughly, so as to bring the coagulated milk into a 
uniform emulsion. A better sample can usually be obtained 



124 



GRADING AND TESTING MILK AND CREAM 



with a dipper. If the milk is not too thick, a fair sample can be 
obtained by the use of the sampling-tube. In order to reduce 
a can of coagulated milk to a thoroughly uniform quality, it is 
best to pour it from one can into another. This mixes it much 
more completely than if the sample were simply stirred with a 
dipper or any other kind of an agitator. 

Apportioning Skim-milk. — The amount of skim-milk to be 




Fig. 38. — Jensen can drier, sterilizer and rinser. 
(Jensen Creamery Machinery Co.) 



received by the patron depends largely upon the thickness of 
cream skimmed, and upon the amount of skim-milk retained at 
the creamery for various purposes. The amount of skim-milk 
generally returned by creameries varies between 80 and 90 per 
cent of the whole milk deKvered. 

Most up-to-date creameries now make use of skim-milk 
weighers. Where such are employed, the man who receives the 
milk hands each patron a check for the amount of milk delivered. 
This check is put into the skim-milk weigher, and it allows an 



WASHING CANS 



125 



amount of skim-milk to flow out, corresponding to the number of 
pounds indicated on the check. 

In case a skim-milk weigher is not employed, it is essential 




Fig. 39. — Hydraulic can washer and dryer. (Creamery Package Mfg. Co.) 

to have a man at the skim-milk tank to weigh out the proper 

amount of skim-milk to each patron. If the patrons are allowed 

to weigh out their own skim-milk, mistakes are frequently made, 

which result in more or less dissatisfaction. It is quite customary 

for butter-makers to 

draw a chalk line on 

the outside of the can 

some distance below 

the surface of the 

milk. This indicates 

the point to which the 

can may be filled with 

skim-milk. 

Washing Cans. — 
The creamery oper- 
ator should make it 
a point to have all 
empty cans thorough- 
ly washed with warm 
water, and then 
steamed and steril- 




FiG. 40. — Hydraulic can washer-rotary type. 
(Rice and Adams.) 



ized, after which hot air should be blown through thoroughly to 
dry the cans. Frequently, bad flavors are transmitted to cream 
from cans that have been closed up tight before being thoroughly 



126 GRADING AND TESTING MILK AND CREAM 

dried. Where hot air is not used, the cans can be turned 
upside-down on a platform with openings to allow air to circu- 
late through the cans, drying them thoroughly before the covers 
are put on. 

Drying cans as above described not only conserves the tin 
of the cans, but also places the cans with the patrons in a clean 
condition, free from bad odors. It also saves considerable 
work on the part of the patrons, as well as insuring them a clean, 
sanitary can. 

One patron told the author that this cleaning of the can was 
worth one cent per pound of butter-fat to him. The creamery 
is equipped to do this can-cleansing better than is the patron 
and it is repaid for this extra labor in a better grade of cream 
and in increased patronage. 



CHAPTER IX 
COMPOSITE SAMPLES 

Definition. — In order to avoid testing each patron's milk or 
cream every day for fat, a small sample, which represents the 
average quality and a proportionate part of the whole, is taken 
from each patron's milk every day and placed in a jar. A pre- 
servative of some kind is previously placed in the jar to keep the 
contents from spoiling. This is called a composite sample. 

When to Sample. — Some makers prefer to sample the milk or 
cream delivered every day; others prefer to sample every other 
day. Some creamery operators, again, sample four or five times 
in succession at intervals, the patrons being unaware of the time 
when the sampling is to take place. The most reliable and prac- 
tical method, however, is to take a sample every day, and test it 
for fat at the end of every two weeks. When cream is received 
composite samples do not give reliable results. In fact this 
system has been very generally superseded by that of weighing 
and testing the cream of each delivery or shipment. 

Kind of Preservatives to Add. While there are several pre- 
servatives that may be used, such as salicylic acid, borax, boracic 
acid, and bicarbonate of soda, those most commonly used are 
bichromate of potash and corrosive sublimate (mercuric chloride) 
either singly or as a mixture. Bichromate of potash, while 
poisonous, is not extremely so and it imparts a color to the sample 
which readily indicates its presence. It has, however, two 
defects; if used in excess it is very much inclined to cause a 
charred or burnt reading when the sample is tested, and if the 
sample be exposed to light for any length of time a leathery scum 
forms on the surface, which it is difficult to dissolve completely 
by means of the sulphuric acid. 

127 



128 



roMi'osi'ri': samtlks 



Corrosive sul)lim;ilr is ii strong iind a very satisfactory 
preservative; bill il is (|uite poisonous, and where the i)ow(ler 
itself, which is white, is used in e()niiH)site samples some kind of 
eoloring matter should always he addi'd to indicate its presence. 
Aeeording to the authors' experience, corrosive sul)limate 
tablets can be highly recommended. The tablets contain a 
color, which, when dissolved, colors milk, so that it can readily 
be <listinguishcd as not being fit for human food. The tablets are 

very [)()isonous, l)ut are more 
elVicient in their i)reservative 
("iTi'ct llum bichromate of 
potash. They can be ob- 
tained fnmi any crcamery- 
sui")ply house. 

During the winter, when 
the sa.mi)les are kej^t com- 
paratively cold, less perserva- 
tive is needed than in tlie 
summer. One corrosive sub- 
FiG. 41.— Composite stiniiilrs and rack to limate tablet Will keep a 
l.old sample- jars. half-pint to a pint of milk 

or cream in good condition for about two weeks in sunmier, 
and about three weeks in winter, i)roviding the sample is properly 
cared for. Some makers are practicing testing at the end of 
every month dining the winter, and every two weeks during the 
sunmuM-. Testing at the end of every month saves labor, but it 
is not a reliable method to follow under all conditions, as some of 
the sani])les are likely to be somewhat unpaired after standing 
so long. 

Arrangement of Composite Samples. — Pint glass jars with 
covers are, so far as known, the most convenient vessels to use 
for comj^osite sami)les. Shelves should be arranged in the weigh- 
ing-room i)n which to kc>ep the bottles. If possible, it is best 
to have them in a case closed with glass sliding doors. This 
is neat, and, if the glass doors iU well, the samples are in some 
measure protinied in case of (|iiick, unexpected changes in tem- 
peratinw These sliding doors should bc> locked whcMi the cream- 




CAMK OF (^oMPosrri': samplks 12!) 

cry operator is absent Iroiii (he creamery, in order to prevent any 
tampering with the eonij)osite samples. 

The best method of arranging the sample jars is to have all 
the jars belonging to the patrons of each route standing in 
one group, or on one shelf, if possible. The bottles are num- 
bered to correspond with the number given each patron on the 
milk sheet. The name of the hauler, or the number of the route 
can be put on each shelf. The samples belonging to those who 
haul their own milk can be ])ut on another shelf; these can be 
designated as individual haulers. Such a. classification, when the 
bottles are plainly numbeied, will often j)revent the mistakes that 
are likely to occur if the bottles are simply numbered and put 
into a rack together. 

Care of Composite Samples, — In the first place, the jars 
should l)e kept scrui)ul()usly dean. The tests are unreliable if 
the jars are left covered with milk and molds round the neck 
from one month to another. When the samj)les have been 
tested the jars should be thoroughly cleaned, tmd, if necessary, 
scalded, before they are used again. Care should be taken to 
spill as little milk as possil)le around the neck, inside as well 
as outside of the bottle, when the sample is put in. If the 
milk is sjiilled there, it gives the bottle an unattractive appear- 
ance. Very often it becomes moldy, and, as more milk is added 
and the samj)le shaken every day, this mold gradually extends 
down the sides of the bottle. This causes the composite sample 
to be infested with undesirable growth, and to spoil sooner than 
it would if greater care were taken in keeping the milk from 
coming in contact with the sides of the bottle before coming 
in contact with the i)reservative. 

A few drops— but only a few — of formaldehyde added to the 
sample, where this is necessary, is a good preventive of mold; 
but this should not be used as a sul)stitute for thorough cleaning 
of the bottles after each test period. 

It is important also that the samj^le jars be well covered; 
otherwise the moisture evai)()ratcs, causing the milk or cream 
to dry up, and, making the test unreliable by increasing the jht 
cent of butter-fat. A gentle rotary motion should be given each 



130 COMPOSTTl'; SAMPLES 

jar when a sample is added to it to mix the cream, which rises to 
some extent after the milk has stood a while. 

Average Sample. — It is sometimes desirable to obtain an 
average test of the milk from a whole day's delivery. This can 
be obtained in two ways: First, by taking a sample from each 
patron's milk with a sampling- tube, and putting all the samples 
together in one jar. The result represents an average test, pro- 
viding the samples have been correctly taken. Second an aver- 
age test can be had by boring a small hole in the conductor-head. 
When the milk passes over this hole, a small portion of it drops 
through. A vessel of some kind can be put underneath to catch 
the drops. Such a drip-sample will represent very accurately 
the average quality of the milk received at the creamery. If it is 
desirable to keep this sample, a preservative can be added to it. 

Composite Sampling without the Use of Preservatives. — 
Pipettes can be obtained holding 5.87 c.c. of milk. These are 
one-third the size of the ordinary 17.6 c.c. pipette used for the 
Babcock test. With this small pipette a sample may be taken 
every day from each patron's milk, during three successive days, 
and emptied into the same test-bottle each day. At the end of 
three days the samples may be tested and the bottles cleaned, 
ready for use again. 

Accurate composite samples may be obtained in this way, 
providing the sample in the pipette is correctly taken each day. 
No preservative is needed. The preservatives are added to the 
composite samples to prevent curdling. The test-bottles may 
be placed on a shelf, or preferably in a rack made to hold them. 
They should be marked in such a way as to identify them. 
A good way is to mark them as the composite jars are marked, 
the number on the test-bottle corresponding to the number on 
the milk-sheet for each patron. 



CHAPTER X 

CREAMERY CALCULATION 

Find the Average Per Cent of Fat. — In calculating the average 
per cent of fat from a number of cows, or the milk furnished by 
the different patrons, the mistake of adding the tests of all the 
samples together and dividing the sum by the total number of 
samples tested is often made. Milk from different patrons, or 
from different cows, will always vary, both in quahty and in 
quantity, and in order to get a correct average test, both quan- 
tity and quality must be taken into consideration. The wrong 
way of calculating the average percentage may be illustrated as 
follows: 



Sample 


Milk Delivered 


Per Cent Fat 


I 


50 lbs. 


S-o 


2 


100 


4-5 


3 


500 


3-0 


4 


300 


3-5 

4)16% 

4 



The average test, according to the wrong method = 4 per cent. 

The correct way of calculating the average percentage may 
be illustrated as follows : 

The average test, according to the correct method, is 3.42 
per cent. 

It will be seen from the example quoted that there is a differ- 
ence of more than .5 per cent. If the percentage of fat or the 

131 



132 



CREAMERY CALCULATION 



Sample 


Milk Delivered 


Per Cent Fat 


I 

2 

3 

4 


50 lbs. 
100 
500 
300 

950 lbs. 


5.0= 2.5 lbs. fat 

4-5= 4-5 
30=15.0 
3-5 = 10.5 

950)32.5 lbs. fat 


3-42 



number of pounds of milk is uniform, it does not matter which 
of the two ways illustrated above is used. But as uniformity 




Fig. 42. — A Russian co-operative creamery in Siberia. 
(U. S. Government Bulletin.) 



in either of these respects scarcely ever exists in practice, the only 
correct way of calculating the percentage is to find the total 
number of pounds of fat and divide it by the total number of 
pounds of milk; the result is .0342, which may be written 3.42 
per cent. 



CALCULATION OF OVERRUN 133 

It is very common for creamery patrons to test the milk 
from each of their cows, then add the tests together and divide 
by the total number of cows tested. The result they will 
call the average test, and frequently such tests are made use of 
as evidence against a creamery operator to prove that his tests 
at the creamery were not correct. The fallacy is evident from 
what has been said above. 

The same mistake is also likely to be made in finding the aver- 
age test from several creamery-plants and skimming-stations. 

Calculation of Overrun. — The amount of overrun is the dif- 
ference between the amount of pure butter-fat and the amount 
of butter manufactured from that given amount of fat. This 
difference, divided by the amount of fat and multiplied by loo 
will give the percentage of overrun. The calculation of the 
overrun in the creamery should always be made from the fat- 
basis on which the patrons are being paid. If the fat is delivered 
in the cream, the overrun should be calculated from the fat in 
the cream. The overrun calculated from the composition of the 
butter manufactured would not be an indication of the correct 
overrun, as there might be serious losses of fat sustained during 
the different steps in the manufacture, such as from inefficient 
skimming, incomplete churning, and general losses in the cream- 
ery. It is possible that butter might show a high content of the 
substances not fat, and yet not show a good overrun on account 
of losses; while butter containing only a medium high moisture- 
content might show as great or greater overrun on account of 
thorough and efficient work during the different steps of manu- 
facture. 
The amount of overrun depends upon: 

1. Thoroughness of skimming. 

2. Completeness of churning. 

3. General losses in the creamery. 

4. Composition of the butter manufactured. 

The theoretical overrun, however, may be quite accurately 
calculated from the composition of the butter manufactured 
in a well-regulated creamery. In creameries where the condi- 
tions of separation and churning are almost perfect, the amount 



134 CREAMERY CALCULATION 

of fat lost in the buttermilk and the skim-milk is quite constant 
from day to day, and should not exceed .i per cent in the skim- 
milk and .2 per cent in the buttermilk, according to the Babcock 
test. Basing the calculations upon the above figures, the theo- 
retical overrun may be calculated from the composition of the 
butter as follows : 

If, for instance, we start with looo pounds of milk testing 
4 per cent fat, there will be a total of 40 pounds of fat. If we skim 
3 2 per cent cream from 4 per cent milk, we should have -A, or | 
of it cream, and the remainder skim-milk, or 125 pounds of 
cream and 875 pounds of skim-milk. If there were .1 per cent 
of fat in the skim-milk, there would be a loss of .875 pound of 
fat during skimming. There would then be 39.125 pounds of fat 
in the 125 pounds of cream (40— .875=39.125). If 10 per cent of 
starter were added to the cream we should get 137.5 pounds of 
cream testing 28.4 per cent. (125 pounds creamXi. 10 = 137.5 
pounds cream; 39.i25-M37.5Xioo = 28.4 per cent fat.) By 
churning this cream we should obtain about 100 pounds of butter- 
milk. If it tested .2 per cent fat there would be a loss of about .2 
pound of fat, making a total loss of fat in skim-milk and butter- 
milk of 1 .075 pounds. Subtracting this total loss of i .075 from 40 
pounds we would have 38.925 pounds of fat left to be made into 
butter (40 — 1.075 = 38.925 pounds of fat). If the butter on 
analysis proves to contain 82 per cent fat, the total number of 
pounds manufactured will be 38.925 -f- .82 =47.47 pounds of butter. 
47.47—40 = 7.47 pounds theoretical overrrun, and 7.47^40X100 
= 18.7 per cent overrun (theoretical). 

It is evident that the losses of fat will vary according to the 
different conditions. The richer the cream, and the less fat in 
the whole milk to be skimmed, the more skim-milk there will be; 
the thinner the cream and the more fat there is in the milk to be 
skimmed, the less skim-milk there will be, and consequently 
with the same skimming efficiency less fat will be lost in the skim- 
milk. The thinner the cream is the more buttermilk there will 
be. These conditions must be left for the operator to govern 
according to the conditions present. 

The actual amount and per cent of overrun as determined 



WHAT SHOULD THE OVERRUN OF CREAMERY BE? 135 

in creameries is calculated as described previously. The formula 
is as follows : 

Butter — fat 

7— X 100 = per cent of actual overrun. 

Calculation of Churn-yield. — Instead of expressing the 
increase of butter over that of fat in the percentage overrun, 
as above, it is often customary among creamerymen to speak 
of the " churn-yield." For instance, they say that their test was 
3.90, and their churn-yield was 5, meaning that on the average 
each 100 pounds of milk contained 3.9 pounds of fat and yielded 
5 pounds of butter. The churn-yield is always expressed in per- 
centage, and is obtained by dividing the total pounds of butter 
obtained by the total pounds of milk from which the butter was 
made, according to the following formula: 

Pounds of butter 

^i; , — - — Tzr- X 1 00 = churn-yield. 

Pounds of milk -^ 

In case cream is handled instead of milk, the same may be 
obtained by substituting " pounds of cream " for " pounds of 
milk " in the formula. 

What Should the Overrun in a Creamery Be? — In discussing 
this problem we shall take 80 per cent as the legal standard for 
fat in butter. If every churning of butter were to drop to this 
standard, but none below it — a thing quite impossible of attain- 
ment — if the patrons were credited with all the fat the creamery 
received, and if there were no mechanical losses, and no fat in the 
buttermilk, then every 80 pounds of milk-fat received would 
make 100 pounds of butter; that is, 100 pounds of fat would 
make 125 pounds of butter, or, the overrun would be 25 per cent. 

The creamery has some gains and some losses which tend to 
offset each other. 

The gains come mainly from two sources, namely, (i) a small 
fraction of a pound of cream on some, but not all, of the cans of 
cream. (2) A small fraction of a per cent of fat on some, but not 
all, of the cream tested. 



136 CREAMERY CALCULATION 

In weighing cream half-pounds should be credited, and in the 
Babcock test of the cream readings should be made by half and 
not whole per cents, thus 30.0 per cent, 30.5 per cent, 31.0 per 
cent, etc., and not 30.0 per cent, 31.0 per cent, etc. 

Following out this principle, the average gain in weight, 
per can of cream, will not exceed a quarter of a pound, and the 
average gain in per cent of fat will not exceed 0.25 per cent. 

The losses may be enumerated as follows: 

(i ) The Loss of Fat in the Buttermilk. — This will, under present 
conditions, easily equal 0.5 per cent. Our extensive investigation 
of the losses of fat in buttermilk, including complete records of 
several hundred churnings in different creameries, shows this to 
be a very conservative estimate; and tests of hundreds of samples 
of buttermilk in the laboratory of the American Association of 
Creamery Butter Manufacturers fully support this estimate. 

(2) Losses in Packing. — Enough butter must be put into a 
package to insure its having the proper weight when it reaches 
the market. 

(3) Mechanical losses, due to cream adhering, to a small 
extent, to the different utensils — cans, vats, etc. Under this 
head may be included the occasional spilling of small quantities 
of cream. 

(4) If practically all of the butter is to come up to the standard 
of 80 per cent fat, the average per cent of fat in the butter will 
exceed this a little. 

(5) If the results of the investigation made by Siegmund 
and Craig, are to be accepted as correct, the Babcock test of 
cream, as ordinarily conducted, gives a reading that is a little 
high. Their findings are summarized in the chapter on " Receiv- 
ing, Sampling, Grading and Testing." 

As a basis for estimating what the overrun in a well-con- 
ducted creamery should be, an 8-gallon can of cream will be taken 
as an average shipment and it will be assumed that the creamery, 
in weighing and testing the cream, credits the patron with 65.0 
pounds of cream testing 30.0 per cent, whereas the actual weight 
of the cream is 65.25 pounds, and the actual test of the cream is 
30.25 per cent. It will also be assumed that in a tub of butter 



= 19. 


5° 


lbs. 


= 19 


■738 




=45 


■5 




= 


.227 


lb. 


= 19. 


Sii 


lbs. 



CALCULATION OF DIVIDENDS 137 

marked 62 pounds, net, there are actually 62.5 pounds of butter 
to allow for shrinkage. 

Amount of fat credited to patron, 30 per cent of 65 lbs. 

Actual amount of fat in cream, 30.25 per cent of 65.25 lbs. 

Weight of buttermilk, 70 per cent of 65 lbs. 

Per cent of fat in buttermilk, o .5 per cent 

Weight of fat in butterm_ilk, o .5 per cent of 45 .5 lbs. 

Weight of fat in butter, 19.738— .227 

Weight of butter made, on basis of 80 per cent fat, ——X 19.511 = 24. ^9 

80 

62 

Weight of butter sold, X 24 . 39 = 24 . 2 

62. s 

24.2 — 19.5 

Overrun X 100 =24. 1% 

19-5 

In the above calculation no account has been taken either of 
the mechanical losses or of the fact that the average per cent of 
fat in the butter will, of necessity, slightly exceed the minimum 
standard of 80 per cent. 

In conclusion, then, we would say that while the overrun 
may, and will, vary to some extent, from day to day and from 
week to week, the creamery that does careful weighing and test- 
ing, and credits its patrons with half-pounds of cream and half 
per cents of fat, will be likely to have an overrun for the year of 
about 23 to 24 per cent. If it has this it is doing careful, efficient 
work. On the other hand, if the overrun is much above or below 
this something is wrong somewhere and needs to be remedied. 

Calculation of Dividends. — The method of calculating divi- 
dends will vary according to the agreements between the manu- 
facturer of the butter and the milk and cream producers. Some 
manufacturers agree to make the butter for so many cents per 
pound of butter (usually 3 or 4 cents) . Occasionally the cream- 
ery proprietor agrees to pay a final fLxed sum for milk delivered 
containing a definite amount of fat (usually 4 per cent). These 
two methods are not in use much at the present time, although in 
the eastern part of the United States the method of paying the 
operator so much per pound of butter-fat manufactured is quite 
common. 

The two methods most commonly used, especially in the 
central West, are as follows: 



138 CREAMERY CALCULATION 

(i) Pay so much per pound of butter-fat based upon some 
standard market price, such as Chicago or New York. The 
amount paid now by the central plants for butter-fat is usually 
2 or 3 cents per pound below " New York Extras," and the com- 
pany pays all freight or express charges. 

(2) Pay per pound of fat based upon the net income of the 
creamery. 

1. The former method of paying for butter-fat has become 
quite common. Nearly all the hand-separator or central plants 
are paying for butter according to this method. Payments are 
usually made at each dehvery or every two weeks. Although 
this causes more work, it is much more satisfactory to the patrons 
than to pay only at the end of each month. 

In order to calculate 'dividends when paid at the end of two 
weeks or at the end of each month, the first step is to find how 
many pounds of butter-fat have been delivered by each patron. 
If composite samples are taken, and these tested for fat at inter- 
vals of one week, which would make about four tests during the 
month, and two during half a month, the results of the several 
tests may be added, and the sum divided by the number of sam- 
ples tested. This may give the average test, but it must be borne 
in mind that this method is also likely to give wrong results. 
Especially is this so when cream is delivered which varies in 
quantity as well as quality during the different parts of the month. 

If cream only is being received, it is a good plan to test each 
patron's cream every day, as it is more or less difficult to get 
absolutely accurate composite samples from creams of different 
richness. Besides this, the patrons can get the test as well as 
the weight of the cream of each previous day's delivery, and thus 
know how their account stands from day to day. A little more 
labor is involved in doing this, but in the long run it keeps the 
patrons better satisfied. 

2. If the price of butter-fat per pound is being based upon the 
net income, as is the case in nearly all co-operative creameries, 
and also in many proprietary creameries, the first step is to find 
out how much butter-fat each patron delivered during the spe- 
cified time, — two weeks or a month, whichever may be the case. 



CALCULATION OF DIVIDENDS 



139 







S 
a 

i-i 
O 



pq 



c 



140 CREAMERY CALCULATION 

When this has been obtained, the total pounds of fat delivered by 
all the patrons are found. From the gross income the total 
expenses of running the creamery are subtracted. The remainder 
represents the net income. This is then divided by the total 
pounds of fat delivered to the creamery, and the quotient repre- 
sents the price per pound of butter-fat to the patrons. 

Knowing the price to be paid to the patrons for i pound of fat, 
the sum due to each patron is found by multiplying the price per 
pound by the total number of pounds of fat each patron delivered 
during the specified time. 

In some instances provisions are made for a " sinking fund." 
This is a name given to a fund raised by deducting so much per 
pound of fat, or per loo pounds of milk, from each patron's 
delivery at the end of each month. This fund is for the pur- 
pose of paying off a debt gradually, or for raising a fund for 
new equipment, or other improvements in the creamery. In 
case such money is to be withheld, it is deducted previous to 
making the final calculation. 

Cream-raising Coefficient. — By the term cream-raising coeffi- 
cient we understand the percentage of the fat removed from the 
milk during the process of separation. The calculation of the 
cream-raising coefficient may be illustrated as follows : 

Suppose we have loo pounds of milk containing 4 per cent fat, 
and yielding 85 pounds of skim-milk and 15 pounds of cream, 
the skim-milk containing .2 per cent fat. 

Total fat in whole milk = 100 lbs. X 4 per cent = 4 lbs. 
Total fat in skim-milk = 85 lbs. X. 2 per cent = .17 lb. 
Total fat in cream = 4 lbs. — .17 lb. =3.83 lbs. 

3.83X100 

= 95.75 per cent of the total 4 pounds of fat, or the 

4 

cream raising coefficient. 

Statement to Patrons. — A complete statement should be 
made at the time of each settlement and should be accompanied 
by the check. A statement similar to the following one may 
serve as an example :i 

^ Creamery Butter-making by Michels. 



STATEMENT OF PATRONS 141 
'. CREAMERY COMPANY 



Mr 

For the month of- 



IN ACCOUNT WITH 



-I92- 



No. pounds milk delivered 

by you 

Average test 

No. pounds butter-fat . 
Price per pound . . . . $ . 



Cr. 



Dr. 



Pounds butter at ... . 

Cans, at 

Cash 

Hauling at. . . . per 100 lbs 



Balance due you 

Total pounds milk delivered at creamery 
Average test at creamery .... 
Total pounds butter-fat at creamery 

lbs. at 



Sales of butter 



Less- 



-cts. for making. 
Balance due patrons . 
Per cent overrun . 
Testing witnessed by 



-Prest. 

-Secy, 



At the end of the year a final statement should be made 
by the respecti^^e officers, similar to the following one: 



ANNUAL REPORT 

Incorporated 192 .... Commenced Operations 192 . . 

Annual Report, 192 ... . 

of the 

CREAMERY COMPANY 

of , , Iowa. 

( Butter-maker; Asst. Butter-maker 



Capital Stock, $ . 



-President, 



Paid in $. 

officers and directors. 

—— — ■ — ■ — Secretary, 



-Treasurer, 



142 



CREAMERY CALCULATION 



SECRETARY'S REPORT 

To the Stockholders: Your Secretary herewith submits the following report 
for the year ending December 31, 192. . . . 

Total pounds of milk received 

Total pounds butter-fat contained in same .... 

Total pounds butter manufactured 

Average test of butter-fat per hundred pounds of milk 
Average yield of butter per hundred pounds of milk . 
Average price paid per hundred pounds of milk 
Average price paid per hundred pounds of butter-fat . 
Average per cent increase of churn over test (overrun) 
Average price received per pound of butter .... 
Average monthly expenses of running creamery 
Average cost of manufacturing butter per pound . 



Following is a Monthly Statement for the year 192. 

January 
February 
March 
April . 
May . 
June . 
July . 
August 
September 
October . 
November 
December 

Totals 



TREASURER'S REPORT. 



To the Stockholders of the^ 



-Creamery Company: Your 



Treasurer herewith submits the following report: 

Statement of Cash Received and Disbursed. 
Receipts Disbursements 

Total Total 

Respectfully submitted, , Treasurer. 

Cashier of Bank. 



PAYING FOR FAT IN CREAM 143 

STATEMENT OF CASH RECEIVED AND DISBURSED 

Receipts. Disbursements. 

Received for butter . . . $ Paid to patrons for milk . . $ 

Running expenses of cream- 
ery and supplies on hand 

Paid for machinery, ma- 
terial, repairs, etc. (out 

of percentage fund) 

Paid dividend on stock for 
192.. (out of percentage 

fund) 

Paid dividend on stock for 
192.. (out of percentage 

fund) 

Total amount of cash re- Total amount of orders 

ceived and paid to Treas- drawn on Treasurer 

urer Cash balance in hands of 

Cash balance in hands of Treasurer, Jan. 192 

Treasurer, Jan. 192 

Total , , Total 

REPORT OF AUDITING COMMITTEE. 

To the Stockholders of the Creamerj; Company: 

We, the undersigned, appointed by your Board of Directors to examine and 
audit the Books, Accounts, and Vouchers of the Secretary and Treasurer of the 

Creamery Company for the year 192. ., hereby certify that we 

have carefully examined the same and compared them with the above reports of 
said officers, and find them correct. 

In witness whereof we have hereunto set our hands at , Iowa 

this .... dsiy of a.d., 192 



Auditing Committee. 



Paying for Fat in Cream Compared with Paying for Fat in 
Milk. — It is evident that when patrons deliver fat in the form 
of milk the creamery operator sustains a loss in the skim-milk, 
while if the fat is delivered in the form of cream, no fat is lost in 
the skim-milk at the creamery, and consequently the cream patron 
should receive more per pound of fat delivered than the whole- 
milk patron provided the quality of the fat in the cream is as 
good as that in the form of milk. The butter-maker slxould 
obtain a larger overrun from the fat of the cream than he does 
from the fat of the milk. The amount which the patrons should 



144 CREAMERY CALCULATION 

be paid for fat, delivered in the form of cream, depends upon the 
thoroughness of skimming. If looo pounds of milk testing 
4 per cent fat were bought and skimmed, there would be a loss 
of about .9 of a pound of fat during the skimming, which would 
make about i pound of butter, worth about 30 cents. If bought 
in the form of cream this loss would not be sustained. The 
above loss during skimming, according to the figures mentioned, 
would amount to about three-quarters of a cent per pound of 
butter manufactured. The fat lost during the skimming process 
would amount to about 2 per cent of the total fat. If the cream 
fat be increased by 2 per cent, an approximate basis for paying 
milk and cream patrons is obtained. 

This argument, however, will hold good only when the cream 
is graded and paid for on a strictly quality basis. This is decid- 
edly the exception, not the rule, at the present time. Milk, 
however, is graded to a much larger extent. If it is seriously 
off in flavor it is likely to be rejected; furthermore, it has to be 
cooled promptly to prevent it from souring, and this holds fer- 
mentations in check. Everything considered, we are quite 
inclined to the view that the cream and milk patrons of a creamery 
should — under present conditions at least — be placed on a par 
as to the price paid them per pound of fat. 



CHAPTER XI 
HEATING MILK PREVIOUS TO SKIMMING 

Reasons for Heating. — Owing to the fact that all separators 
will skim closer and not clog so easily when milk is heated, nearly 
all creameries heat or warm the milk previous to skimming. 
When the milk is thus heated and stirred in a pure atmosphere, 
many undesirable odors or taints escape. With an increase of 
temperature, the viscosity of the milk is lessened, due chiefly to 
the softening and separation of the fat- globules. Such an 
increased fluidity of the milk lessens the resistant force of the 
fat-globules when exposed to the centrifugal force of the sepa- 
rator. The higher the temperature the more fluid the milk 
becomes, and consequently the more easily the fat can be sep- 
arated. 

By warming the milk to a high temperature and leaving it for 
some time, then cooling quickly again to skimming temperature 
(90° F.) and separating, the skimming efficiency of the separator 
is increased materially. If the milk has been standing at a very 
low temperature for at least three hours, and then is quickly 
warmed up to the usual skimming temperature, and skimmed, 
the warming of the milk has comparatively little effect in bringing 
it into a good condition for skimming. It will thus be seen that 
it is possible to skim milk at the same temperature, and yet get 
different results, due to previous temperature conditions. Dura- 
tion of temperature should be considered as well as the tempera- 
ture itself. 

The temperature to which milk should be heated previous 
to skimming varies according to different investigators. The 
temperature mostly employed in the past in this country, and 
perhaps at the present time, is about 90° F. This comparatively 

145 



146 HEATING MILK PREVIOUS TO SKIMMING 

low temperature was fixed owing to the supposedly bad effect 
high skimming temperatures had upon the body of the finished 
butter. Exposing milk at high temperatures to the centrifugal 
force in a separator was said to produce a greasy body in butter. 
According to experiments conducted at the Iowa Experiment 
Station by the authors, milk can be skimmed at 175° F. without 
any injury to the quality of the butter, providing the cream 
is cooled to ripening temperature, or below, as soon as it has 
been skimmed. After the ripening has been completed the 
cream should be exposed at least three hours to a low tempera- 
ture (50° F.) previous to churning. 

If the milk is heated in any of the best modern heaters, there 
will be no injurious results to the quality of the butter. Pro- 
fessor Dean, at the Ontario Agricultural College, has also found 
it practical to heat to pasteurization temperature previous to 
skimming. In many creameries in Denmark this method of 
heating milk is also followed. The Danes, as a rule, however, 
pass the heated milk over a cooler before it goes into the sep- 
arator. 

The chief difficulty encountered by the authors in heating 
milk to such a high temperature previous to skimming was 
that the upper bearing in the separator got so hot that it was 
deemed injurious to the separator, although the bearing did 
not heat to such an extent as to cause the running of the machine 
to be abnormal in any way. 

Advantages of Warming Milk to High Temperature Previous 
to Skimming. — The advantages of heating milk to a high tem- 
perature (175° F.) previous to skimming may be summarized as 
follows: 

(i) Undesirable taints are eliminated from the milk to a 
greater extent than can be accomplished in any other way, 
without applying chemicals. 

(2) The heating of whole milk destroys the germs in the 
resultant skim-milk and cream practically as efficiently as when 
they are heated after the skimming process has been completed. 

(3) Less heating and cooling apparatus is necessary. 

(4) Closer skimming is possible. 



HOW HEATED 



147 



How Heated.— There are two methods by which milk is 
heated previous to skimming. First, by the use of direct hve 
steam; second, by the use of heaters which heat with steam or 
hot water indirectly. 

Heating of milk with direct live steam is accomplished in 
two ways: first, by entering a steam hose into the vat full of 
milk; and, second, by making use of special heaters, which allow 
steam to come in direct contact with the milk as the milk passes 
through. 

The method of heating milk with direct live steam cannot 
be too strongly condemned, because it has a bad e-ffect upon 
the flavor of the butter. At the Milwaukee National Butter 




Fig. 44. — The Twentieth-century milk-heater. 



contest in 1903, where over eight hundred exhibitors were 
represented, the authors noticed that where the criticism 
" burnt," "oily flavor " was made on the score card, the milk 
from which the butter was made had in most cases been heated 
with Uve steam. The burnt flavor may possibly be due to the 
sudden excessive heat to which the milk will be exposed when 
coming in contact with live steam. The greatest danger, 
however, in heating milk with Hve steam is, that impurities 
from the pipes and boiler are likely to be transmitted to the 
milk, and cause bad flavors. In most of the creameries the 
exhaust-steam from the engine is used to heat the water for the 
boiler. This steam is likely to carry with it cylinder-oil, which 
will impart undesirable flavors to the butter. Some creameries 
are also using boiler compounds for the removal of scales. These, 



148 HEATING MILK PREVIOUS TO SKIMMING 

when subjected to high heat and pressure, are Hkely to be 
transmitted to the steam-pipes, and from there with the steam 
into the milk. The scale and rust of steam-pipes are also likely 
to be transferred to the milk. 

The right way to heat milk previous to skimming is to make 
use of one of the special heaters on the market, which heat by 
the use of steam or hot water indirectly. 



CHAPTER XII 
SEPARATION OF CREAM 

In the process of the manufacture of butter it is essential 
that the fat of the milk, shall be concentrated into a compara- 
tively small portion of the milk serum. This concentration of 
fat carries with it a portion of all the other milk constituents, and 
the product is called cream. It is possible to churn milk with- 
o ut a ny separation, but a much greater loss is attendant, if the 
fat is not brought together by the process called separation. 

The different kinds of cream may be classified according to 
the different methods of cream-separating: 

r Shallow-pan cream. 
Gravity cream ■ ■ ■ \ Deep-setting cream. 



Cream ■ 



Centrifugal cream 



Water dilution cream (hydraulic). 

Hand-separator cream. 
Creamery-separator cream. 



GRAVITY CREAMING 

Shallow-pan System. — This method of creaming is used 
mostly on farms which are situated unfavorably in relation to a 
creamery, or for some other reasons do not send their milk to 
the creamery. It consists in placing the milk in shallow pans, 
from 2 to 4 inches in depth, as soon after milking as possible. 
The milk is then placed where it can be quickly cooled to a 
temperature of at least 60° F. A lower temperature than this 
is desirable if conditions permit, The atmosphere in the room 
in which the milk is standing must be pure, free from dust, 
draught, and any undesirable taints or odors, since it takes 
about thirty-six hours of quiet standing for the cream to rise. 
If there is a constant current of air in the room, a leathery 

149 



150 



SEPARATION OF CREAM 



cream is likely to form. At the end of this time the cream is 
rem.oved by the use of a skimmer, m.ade especially for this pur- 
pose. It is difficult, however, to remove all the cream by this 
means. The perforated skimmer should never be used. It 
allows the thin under-layer of cream to run through and be lost 
in the skim-milk. 

If the conditions are such that cool water can be constantly 
circulated around the pans containing the milk, the temperature 
can easily be made to go below 60° F., and the creaming process 
is facilitated. When such conditions are present, the depth of the 
milk in the pans can safely be increased to about 6 inches. Under 

the most favorable conditions about 
.5 per cent fat will remain in the skim- 
milk. 

Deep-setting System. — This system 
is undoubtedly the best method of 
gravity creaming. When it is properly 
carried on the fat can be removed so 
completely that no more than .2 per cent 
of fat remains in the skim-milk. It con- 
sists of putting milk into deep cans 
(ordinary four-gallon shotgun cans are 
usually employed) immediately after the milk has been drawn 
from the cow. Then it is put into cold water, and generally 
cooled down to, and maintained at, a temperature of about 
55° F. The cream will rise in about twenty-four hours. Better 
results can be obtained if the water is cooled down to about 40° 
with the use of ice. 

One reason why this system is so much in use, even in cream- 
ery localities, is that the cream obtained is nearly always of a 
good quality. The farmer knows that unless the milk be cooled 
quickly, and maintained at a low temperature, the cream will not 
rise freely. For this reason the milk is systematically and thor- 
oughly cooled, which is one of the great essentials in checking the 
growth of the ferments in milk and keeping the milk in good con- 
dition. In m.any parts of the eastern United States, the deep- 
letting system is in general use. A special form of can is used, 




Fig. 45. — Cooley creamer 
and elevator. 



GRAVITY CREAMING 151 

it is simply an ordinary four-gallon can, about 8 inches in diarreter 
and 20 inches deep. It has a glass on one side near the bottom or 
near the top, which allows the reading of the thickness of the 
layer of cream. On each side of the glass is a graduated scale, 
which gives the reading in inches. In case the cream is being 
sold to a creamery, the hauler comes along, notes the depth of the 
layer of cream, and records the number of inches of cream oppo- 
site the patron's name. At the end of the month, or whenever 
the time for payment comes, the money is apportioned according 
to the number of inches of cream delivered by each of the patrons. 
No test for fat is made. This is what is known as the " Cooley 
system," and is used quite extensively in the East, especially in 
Massachusetts. 

While cream usually arrives at the creamery in a fair condition, 
there is the objection that the cream is always thin. It seldom 
contains any more than 18 or 20 per cent of fat. 

No good explanation has yet been given why cream in a deep 
layer of milk at 40° F. should rise more quickly and more com- 
pletely than in a thin layer at a higher temperature. Arnold ^ 
seeks to explain it by saying: " Water is a better conductor of 
heat than fat; hence when the temperature of the milk varies 
either up or down, the water in the milk feels the effect of the 
heat or cold sooner than the fat in the cream does. Therefore 
the cream is always a little behind the water in swelling with heat 
or shrinking with cold, thus diminishing the difference between 
the specific gravity of the milk and cream when the temperature 
is rising, and increasing it when the temperature is falling." 

This explanation is, according to Babcock,^ not satisfactory. 
He says: " Though it is true that water is a better conductor 
of heat than fat, the small size of the fat-globules renders it 
impossible that under any circumstances there can be more than a 
small fraction of a degree of difference between the temperature 
of the fat and that of the milk serum. Moreover, with the limits 
of temperature practical for a creamery, (90° to 40° F.), the 
coefficient of expansion of butter-fat is more than three times as 

1 American Dairying, p. 210. 

^Wisconsin Experiment Station, Bull. 18, p. 24. 



152 SEPARATION OF CREAM 

great as that of water, so that in order to maintain the same rela- 
tive difference in their specific gravities when the temperature is 
falling, the milk serum must cool nearly three times as quickly 
as the fat. In other words, when the milk serum has cooled from 
90° to 40°, or 50° F., the fat-globules should have lost less than 
17°, and should still have a temperature of over 70° F., a differ- 
ence between the temperature of milk serum and fat of more 
than 33°. Such a condition is manifestly impossible, but 
a less difference than this would cause the fat to become 
relatively heavier than at first, and would operate against the 
creaming." 

A low temperature increases the viscosity of the milk, and 
consequently it would seem that the resistant force of the fat- 
globules in their upward passage through the milk serum would 
be increased, and thus retard the creaming. Babcock maintains 
that fibrin is partially precipitated when milk is allowed to stand 
at a medium high temperature. The fibrin, when precipitated, 
forms a fine network of threads permeating the milk in all direc- 
tions, similar to the network of fibrin in coagulated blood. It is 
possible to conceive that such a network would interfere with the 
rising of the fat-globules, at comparatively high temperatures. 
The reason that fat-globules will rise more quickly and more 
completely in the deep-setting system than in the shallow-pan 
system, might be explained on this fibrin theory were it not for the 
fact that experiments conducted at the Cornell Experiment 
Station show that the setting and cooHng of milk may be delayed 
long enough for this fibrin to form, without any effect upon the 
separation when set and cooled. 

Probable Explanation. — There are two factors which, taken 
in conjunction with each other, seem to offer a reasonable 
explanation of the efficiency of the deep-setting system. 

The first of these is that cooHng the milk to, and holding 
it at, a low temperature keeps the milk serum in a much better 
physical condition. It may not be so fluid as it would be at a 
higher temperature, but there is a minimum formation of fine 
masses or particles of curdy matter that would either imprison 
some of the fat or offer obstruction to the fat-globules, and 



GRAVITY CREAMING 153 

clusters of globules, in rising. It is a fair assumption that in the 
experiment at the Cornell Station the milk was not held long 
enough, before cooling, seriously to impair its physical condi- 
tion. 

The second very probable factor is that of the formation of 
fat clusters, through large fat-globules rising faster and coming 
into contact with smaller ones. These and other clusters would 
continue to pick up isolated globules and smaller clusters, and so 
the process would continue; clusters would, of course, rise more 
readily than individual globules, and larger clusters would rise 
more rapidly than smaller ones. The result would be that, 
owing to the good physical condition of the milk — the absence 
of casein particles to enmesh the fat-globules and offer obstruc- 
tion — practically all the fat-globules would find their way to the 
top. 

Water-dilution Cream (Hydraulic.) — It was thought, at one 
time, that a modification of the deep-setting system, through 
the dilution of the milk with water to the extent of 25 per cent to 
50 per cent, would greatly add to its efficiency, through reducing 
the viscosity of the milk. The idea was, of course, commercial- 
ized and a number of so-called " dilution cream separators " 
were placed on the market. The method is still practiced 
to some extent, but it is by no means as general as it was at one 
time. 

While it is true that under very exceptional conditions — such 
as in setting the milk of an occasional individual cow near the 
end of her lactation period — some advantage may be gained, the 
principle has no general application. It must be remembered 
that, while the addition of water to milk makes it more liquid, it 
also reduces the difference in specific gravity between the m.ilk 
serum and the butter-fat, and it is upon this difference that we 
depend to bring about a separation. 

Even though the skim-milk should, at times, show a lower 
per cent of fat, this is only an apparent advantage, as there is a 
much greater quantity of it. Wingi obtained the following 
results with diluted and undiluted milk: 

^ Milk and Its Products, p. 105. 



154 SEPARATION OF CREAM 

Diluted with 25 per cent water, set at 60° F. (39 trials), 0.77 
per cent fat in the skim-milk. 

Undiluted, set at 60° F. (30 trials), i.oo per cent fat in the 
skim milk. 

Undiluted, set at 40° F. (30 trials), .29 per cent fat in the 
skim-milk. 

A test of .77 per cent, where the milk is diluted to the extent 
of 25 per cent, means a greater loss of fat than where the skim- 
milk from undiluted milk tests i.oo per cent. 

It will be noted that, in his trials under the dilution method, 
Wing set the milk at 60°. The reason for this was that advocates 
of the system contended that it would bring about such a speedy, 
and yet complete, separation that it was unnecessary to adopt 
low temperatures. Wing's experiments prove two things; 
first, that whether milk is diluted or undiluted the loss of fat is 
heavy if the setting temperature is high, and, second, that where 
the milk, without dilution, is set at a low temperature the cream- 
ing coefficient is quite satisfactory. 

The valid objections to the dilution method are as follows : 

Much more bulk to handle, the use of a larger number of cans, 
and increased labor. 

Danger of contamination of the milk and cream through the 
use of impure water. 

Impairment of the value of the skim-milk for feeding. 

Injury to the cream or butter — the product has an unde- 
sirable, flattish flavor. 

The loss of fat in tlie skim-milk is too great, as the experiments 
by Wing show. 

CENTRIFUGAL CREAMING 

In the separation of cream by centrifugal machines, the 
same principle is used as in the gravity system of separation. 
The only difference is that in the centrifugal method the force 
which separates the cream from the milk is generated by artificial 
methods, and acts in a horizontal direction; in the gravity system 
the force which separates the cream from the milk is only that 
which results from the difference in the specific gravity of the 



CENTRIFUGAL CREAMING 155 

cream and the skim-milk, and the force acts in a vertical direc- 
tion. The force generated in the separator is several thousand 
times greater than the natural force in the gravity method. 
For this reason the cream separates almost instantaneously after 
the milk has entered the separator and is exposed to the cen- 
trifugal force. 

Advantages. — The centrifugal separator has several advan- 
tages over the gravity method, which are apparent without 
detailed elaboration. In the first place, the range of tempera- 
ture and condition of the milk at which the cream can be suc- 
cessfully separated is much greater than that for successful 
separation by the gravity method. Second, a much better 
quality of cream can be obtained by the centrifugal system, 
as the separation can be done before the milk gets old, while 
by the gravity method the time required for efficient separation 
is so long that the cream deteriorates more or less before it is 
removed from the milk. Third, by the centrifugal method the 
thickness of the cream can be regulated to suit requirements, 
while by the gravity method the thickest cream that can be 
obtained is about 20 per cent. Fourth, by the centrifugal method 
many impurities and undesirable germs are removed, while in 
the gravity method the exposure to open air, more or less impure; 
is Hkely to contaminate the milk with taints, and also allows the 
germs to fall into it. Fifth, by the centrifugal method the skim- 
milk is left in a more natural condition. The milk can be 
skimmed soon after milking, or after it has been delivered to the 
creamery, and thus be in the best possible condition for feeding 
purposes. Sixth, the centrifugal method permits of a more 
thorough separation of the fat. Butter-fat, as a rule, is too 
expensive to feed, when good and much cheaper substitutes can 
be had. 

History of Centrifugal Separators. — The first centrifugal 
separator was a very simple one. It consisted of buckets hanging 
on the ends of arms, or on the periphery of a rotating horizontal 
flat wheel which swung on a central axis. The milk was placed 
in the buckets and whirled for a time, and then the machine (if 
we may call it such) was stopped, and the cream removed in the 



156 



SEPARATION OF CREAM 



same way as in the gravity system. This method of separation, 
according to J. H. Monrad/ had its origin in 1864. As early as 
1859 Professor Fuchs of Carlsruhe, Germany, suggested testing 
the richness of milk by swinging tubes holding the samples of 
milk. In 1864 Prandtl, a brewer of Munich, separated milk by 
such a device. In 1870 Rev. F. H. Bond, of Northport, Massa- 
chusetts, worked out a method of separation which consisted of 
two small glass jars attached to a spindle making 200 revolutions 
per minute. By one hour's whirling the cream was brought to 
the top. 

In 1875 Prandtl exhibited at Frankfort-on-the-Main a con- 




FiG. 46. — First centrifugal separator. (From Dairy Messenger.) 

tinuous separator, which did not at the time attract much atten- 
tion, due chiefly to the excessive amount of power needed to 
overcome the resistant force of the air. In 1876 a Danish engi- 
neer named Winstrup succeeded in improving the old bucket 
method. In 1877 Lefeldt and Lentch offered for sale four con- 
tinuous separators with different capacities (from no to 600 
pounds of milk per hour). During that year also, the first 
practical centrifugal creamery was established at ELiel, Germany. 
In 1877 Houston and Thompson of Philadelphia filed a patent for 
the continuous method of separation of cream from milk. The 
patent was allowed in 189 1. In March, 1877, Lefeldt and Lentch 

1 Dairy Messenger, Oct., 1892, p. 109. 



CENTRIFUGAL CREAMING 157 

invented a separator similar in construction to the hollow bowl — 
a more recent type. This machine did not revolve at so rapid a 
rate as our modern machines do, nor did it have arrangements for 
continuous inflow and discharge. It was intermittent in its 
work, and it was necessary to stop at intervals to remove the 
cream and skim-milk. The year 1879 marked the greatest 
advancement toward the perfection of modern separators, in the 
appearance of the Danish Weston, invented in Denmark, and 
the De Laval, invented in Sweden during that year. This led 
to continuous milk and cream discharges, and consequently also 
to the continuous inflow of whole milk. These machines were 
of the hollow-bowl construction. 

Modern Separators. — Since the year when the Danish Weston 
and the De Laval machines were invented, many different 
types of separators with different contrivances within the bowl 
have been put upon the market. Baron Bechtelsheim, of 
Munich, is given the credit of having discovered that certain 
contrivances on the inside of the machine increase the efficiency 
and capacity for skimmxing. This discovery was made, accord- 
ing to J. H. Monrad,! in 1890, This invention was bought by 
the De Laval Company. 

The principal part of practically all the separators is a bow 1 
rotating in a vertical position, with or without contrivances 
inside the bowl. Machines having a bowl rotating in a horizontal 
position are, so far as the authors know, not in use at the present 
time. Such a machine was once manufactured at Hamburg, 
Germany, and was called " Peterson's Centrifugal Machine." 
Another German machine, called " The Page," was also manu- 
factured in the horizontal bowl style. 

From the above it will be noticed that four separate steps 
are recognizable in the evolution and improvement of separators : 

1. Revolving Bucket Centrifuge; 

2. Intermittent Hollow Bowl; 

3. Continuous Hollow Bowl; 

4. Continuous Separator with contrivances within the Bowl. 
The science and practice of separation of milk and cream have 

^ Dairy Messenger, Jan., 1892, d. 9. 



158 



SEPy\RATION OF CREAM 



seemingly reached a high state of efficiency. It seems almost 
improbable, considering the many new improved separators on 
the market, that any other great improvement could be made 
which would add a separate stage to the improvement of our best 
centrifugal milk separators of to-day. 

Classification of Separators. — Owing to the many different 

standard types of separators 
now on the market, it is im- 
possible to describe each one 
in detail. For this reason the 
classification appearing below 
has been made. There are 
undoubtedly many other 
types, especially in foreign 
countries, with which the 
writers are not familiar, and 
which are not mentioned 
here. The following classi- 
fication will, in some meas- 

,^. , , ure, illustrate the different 

\ C*** ^\ makes of separators on the 

X^teiBrf**^ -a^ market to-day: 

Many of these separators 
which cause the milk to pass 
up and down in vertical sheets have the bowl contrivances corru- 
gated and perforated with holes so that the skim-milk and cream 
also assume a partly horizontal direction. 

Process of Separation. — From the illustrations, the structure 
of the more common types of separator bowls is readily under- 
stood. The whole milk may be made to enter at the bottom or 
top of the bowl when revolving. In the Sharpies, it enters at the 
bottom, the more common way is to have it enter at the top. 
As the milk enters the bowl and is exposed to the centrifugal force, 
it immediately begins to separate into three distinct layers. The 
centrifugal force acting in a horizontal direction forces the 
heaviest portions of the milk and the precipitated albuminoids, 
ash, filth, and a multitude of germs over next to the wall of the 




I'k; 



The Simplex separator. 



A7 



CENTRIFUGAL CREAMING 



159 



Separators 





Hollow bowl. . . ■ 


t Sharpies. 


Omega 






Cause milk to 


Empire. 






pass in thin 


Davis. 


Farm sep- 




sheets verti- 


United States. 


arators. 




cally in bowl 


National. 
. Reid. 




Contrivances 
in bowl. 




Dairy Queen. 
De Laval. 




Cause milk to 


Peerless. 






separate into 


Swea. 






almost hori- 


WestphaHa 






zontal thin 


(Cleveland) 






sheets. 


Iowa. 

Internat. Cream 
Harvester. 



Creamery 
power 
separa- 
tors. 



Hollow bowl 



Improved Danish Weston (Reid.) 
Sharpies (old style). 
De Laval (old style). 



Contrivances in 
bowl. 



Cause mUk to 
pass in thin 
sheets verti- 
cally in bowl. 

Cause milk to 
separate in al- 
most horizon- 
tal sheets. 



United States. 
Simplex. 
Sharpies (new 
style). 



De Laval. 
Springer. 



separator bowl, and into a solid and more or less gelatinous layer, 
which is known as the " separator slime." In very impure milk 
this substance is so plentiful that it is likely to clog the separator 
in a very short time, and before much separation is accomplished 
it is necessary to clean out the bowl. The second layer is the 
skim-milk, while the cream, being the lightest, is forced to the 
center of the bowl and forms the third portion mentioned. There 
is no distinct line of demarcation between the layers of skim-milk 
and cream. They overlap each other and form a sort of zone, 
rather than a sharp separation. The richest cream is nearest the 
center of the bowl, and gets thinner toward the outer portion of 
the bowl; consequently, by turning the outlet for the cream, or 



160 



SEPARATION OF CREAM 



cream screw, nearer the center of the bowl, the cream is increased 

in richness. Turning it away 
from the center causes the cream 
to be thinner. The skim-milk 
that is forced clear to the cir- 
cumJerence of the bowl contains 
the least fat, and consequently 
the skim-milk is always first 
removed from this portion of 
the bowl. Usually the skim- 
milk outlet is brought in towards 
the center of the bowl at one end 
through tubes extending from 
the circumference of the bowl. 
If this were not done, some difh ■ 
culty would be involved in arranging a receiving-pan for the dis- 
charged skim-milk. If the skim-milk were discharged near the 
circumference of the bowl, it would come out with a heavy force. 




Fig. 48. — The Reid separator. 





Fig. 49. — Showing "butter extractor" 
attached to De Laval separator. The 
butter extractor is not known to be 
in use now . 



Fig. 50. — Showing cross-section 
De Laval separator bowl. 



of 



CONDITIONS AFFECTING EFFICIENCY OF SEPARATORS 161 

Also, if the outlet for the skim-milk were near the circumference 
of the bowl a great deal more power would be required to run 
the machine. As the skim-milk passes through the tubes 
towards the center it gives up its force. The nearer the skim- 
milk outlet can be brought to the center of the bowl, the more 
easily will the machine run. 

The size of the skim-milk outlet is usually such that it bears a 
certain relation to the size of inlet, size of bowl, and speed of the 
machine. Most skim-milk outlets are made so as to discharge 
from .4 to about .9 or a Httle more, of the whole milk that enters 
the bowl. The remainder is the cream, which is forced to the 
center of the bowl and discharged through the cream outlet. 

CONDITIONS AFFECTING EFFICIENCY OF SEPARATORS 

I. Manner of Heating Milk. — Owing to the fact that fat- 
globules rapidly change their shape and properties when exposed 
to heat and excessive agitation, it is essential that care 
should be taken in heating milk previous to skimming. When 
fat-globules are heated they become more liquid, and if stirred 
very much the clusters of fat-globules break up more rapidly. 
The individual globules, if stirred violently, will break or sub- 
divide into several small ones. The higher the temperature 
of the milk, the more fluid it becomes, and the easier the separa- 
tion. If milk is stirred violently, the individual fat-globules 
break up into smaller ones, which are separated from milk with 
difficulty. The table^ on p. 162 illustrates what effect the dif- 
ferent degrees of agitation of milk have upon the efficiency of 
separation. 

In the experiments the diameter of the agitator in the pas- 
teurizer was 14 inches. The speed at the periphery, at 250 
revolutions per minute, was 15 feet per second. 

It will be seen from the table (p. 162) that the higher the speed 
of the agitator, the greater the difficulty in getting a complete 
separation. Besides the speed of the agitator in the heating 
apparatus, undoubtedly the shape of the pasteurizer is a factor 

^ Hoard's Dairyman, Fort Atkinson, Wis. 



Ii)'2 



SIOI'AUA'noN Ol' CKI'lAM 



Milk 
Milk 
Milk 
Milk 
Milk 
Milk 
Milk 
Milk 
Milk 
Milk 
Milk 



liciilcd ill v:il, mil |>iiiii|)(;(l 

licatcd in iwiHlciirizcr, 200 rev. of !iKilii.l(ir imt luin 
lu'iilcd in piiHlcurizor, 250 rev. of iiKiiiilor per min 
Iu'iiUhI in paHleurizcr, 300 rev. of anilalor pti miii 
liealcd in paslcnrizer, 350 rev. of af.^ilalor per min 
iicalcd in paslfiM'izer, 400 rev. of ai-fitiiloi pir min 
lif.'ilcd in paslfiirizer, 500 rev. of aKilalor per min 

|)iim|)cd by the liirliinc pninp a,( 1 22" V 

pninpcd by llic Iniliinc piinip a! 04" 1'' 

pumped willi I lie pump, elTci live a,l \r}.° 

piimpt'd willi lln- pump, cHci live .'il (),[" 




in (Iclcniiininj!; Ilic cnuicncy of llic su1)sc'(|iu'm( s('|);i.r;iti()n. For 
inslaiicc, tlic milk in iiiosi hoii/oiilnl paslcuiizcis is, i'Vcmi at low 
S|)('('(l, cxixi.scd lo (•<)iisi<l(ial)lc a|!;ilalioii. 

II (lie milk is suddenly licalcd I'loni a low (ciniH'ra.tiiiT lo 
aJ)oiil Mo" 01 ()()" K. and I hen skiinmcd, (lie lu-alinjj; docs not 
lacililalc llic skimmiii;^' process very niiicli. Il is cssenlia,l llia.t 
llie milk he exposed to lliis lempeiatui-e i'oi" a coiisideiahle lime. 
Tlu' la.l j;lo|)ules do not warm as rapidly as the milk si'nmi. This 
diininishes the dilTerciice helweeii the specific ^Mavily ol" llu" two 
Sllhstaiices, ((iiise(|iieiil ly «()mplcteiiess ol' separation heconu'S 
more dilluult. II' milk is heated to a hij^h lemperature, say, h)r 
iiistancf, 170" I'"., Ilu> separation will he sullicicntly complclc 
without exposing the milk lor any length ol' time to that IcniiKT- 
ature. 

Machini^s are now made, and are on tlie market, which will 
hring tlu> milk inlosuth a (ondition that tlu- I'at glohuies cannot 
he separated liom it. I'he pioi tss is called " homogcnizalion." 
Il ((insists ol hrinj-iuf- the milk (md("r certain i)ressure, and then 
h)r( ing it out through a special valve, 'i'his relief, through Ihis 
spe(ial valve, hreaks uj) the existing fat glohuies into very 
minute ones, vvhi( h cannot he separated Irom the nu'lk hy 
gravits' mehlods, and which it is impossihk' to sei)arale com- 
pl(>tely h\' (cntrifugal methods. 1 lomogeni/ation of milk is 



CONJJITIONS AFFECTING EFFICIENCY OF SEPARATORS 1G3 

carried on to some extent in Europe. The process practically 
insures uniform quality to the milk patrons in the distribution 
of milk in cities, and secures a more uniform consistency of the 
product. 

2. Condition of the Milk. — In order to get complete separa- 
tion, and keep the separator in good running order, it is essential 
that the milk should be in as good physical condition as possible. 
Coagulated, slimy, or otherwise viscous milk separates with 
difhculty. When such milk is on hand it should not be mixed 
with the milk that is in good condition, as it might tend to coag- 
ulate more of the good milk, and the coagulated or slimy lumps 
are likely to clog the separator. Such milk should be left until 
all the good milk has been separated. Then, if the coagulated 
or slimy milk is thoroughly stirred so as to reduce its lumpiness, 
it may be run through the separator successfully. It is a good 
plan not to feed the separator quite so heavily when this quality 
of milk is being run through. If the inlet is partly shut off, it will 
usually run through without clogging. Milk containing impuri- 
ties in suspension should be thoroughly strained previous to 
separation. 

Overfeeding the Separator. — When a separator is being over- 
fed with milk there is a tendency for the machine to do less com- 
plete work. This is due to the fact that the more milk is being 
fed into the separator the less time it will be subjected to the 
centrifugal force. It is possible to underfeed the separator as 
well. As has been mentioned before, the inlet can be closed to 
such an extent as to cause nearly all the discharge to take place 
through the skim-milk tube. 

As a rule when the machine has been set so as to allow the 
milk to flow in at a certain rate, it will continue to admit prac- 
tically the same amount of milk all through the skimming period. 
Among the conditions which may alter the rate of inflow to some 
extent, are the amount of heat and the change of pressure, due to 
different amounts of milk in the receiving-vat. Temperature 
will slightly affect the rate of inflow. The higher the tempera- 
ture, all other conditions being the same, the more milk will joass 
through the inlet. 



164 SEPARATION OF CREAM 

3. Speed. — All modern machines have a device by which their 
speed can be determined. Most speed indicators consist of a 
little wheel, which, when pushed up against the spindle of the 
separator while running, turns around and permits the calcu- 
lation of the speed of the separator. If the wheel on the speed- 
indicator makes 10 revolutions during ten seconds, the machine 
turns 1000 times during the same time. During one minute the 
separator will run six times as many revolutions, or 6000, as ten 
seconds is one-sixth of a minute. Most speed-indicators are so 
adjusted as to turn one revolution for every 100 revolutions of the 
machine. The higher the speed, the more thorough is the sepa- 
ration. Nearly all machines are balanced to do the best work at a 
certain definite speed, varying with different machines, and 
indicated in the directions for operating. It is essential that the 
machine should be brought up to speed gradually, and no milk be 
allowed to flow through it until after it has acquired its full speed. 

During the run, all machines are likely to vary more or less 
in speed, owing to different causes. Pulleys are likely to slip 
on the shaft, and belts are likely to become loose, and thus 
cause variations in the speed. The steam pressure may get low, 
and cause all of the machinery in the creamery to run more 
slowly. This cause, however, is not a very common one where 
belt separators are used. If the engine has an automatic gov- 
ernor on it, the speed is usually quite uniform. Where steam- 
turbine machines are used, the speed of the machine is more likely 
to vary with the different amounts of steam pressure on the 
boiler. With turbine separators it is very essential to keep an 
even steam pressure. Some turbine separators have a safety- 
valve attached to prevent too high speed. 

The reason why the prevention of a variation in speed is so 
essential is that a shght variation in the speed has a compara- 
tively large effect upon reducing or increasing the centrifugal 
force. The centrifugal force generated in a machine varies 
according to the diameter of the bowl, and according to the 
speed of the machine. The greater the diameter of the bowl, 
the less speed or velocity is required in order to get a certain 
force. The centrifugal force varies in direct proportion to the 



CONDITIONS AFFECTING EFFICIENCY OF SEPARATORS 165 

diameter of the bowl; that is, if the diameter of the bowl be 
doubled, then at the same speed, the centrifugal force has been 
doubled. The centrifugal force varies in quadratic proportion 
to the speed of the machine; that is, if the speed of the separator 
is doubled, the centrifugal force is increased four times. From 
this it will be seen that speed is a great factor in determining the 
centrifugal force generated. It is not a good plan to have the 
diameter of the bowl too large, for the following reasons: A large 
bowl is more likely to be thrown out of balance; it is harder to 
keep on the bearings; and it is heavier and more unhandy to 
handle. For these reasons it is better to lessen the diameter of 
the bowl and increase the speed. This, of course, is true only to a 
certain limit. 

Steadiness in Running. — Smooth running of a separator is 
one of the first essentials. If a machine runs roughly, there will 
not be good separation, and it is dangerous to run it. The 
bowl itself is likely to jump out, or burst. The causes for 
unsteadiness in running are many. It may be due to a bent or 
sprung spindle ; the machine not standing level ; changing covers 
to bowls; using clamps which do not fit the bowl cover; unclean, 
worn-out bearings; condition of the bowl, and contrivances 
inside the bowl; and dented and rusty bowls. Occasionally it 
happens that a machine is run backwards. This is likely to 
cause the cover of the bowl to run off. 

Thickness of Cream. — The efhciency of skimming depends 
to some extent upon the thickness of the cream skimmed. Most 
separators, however, will skim within quite a wide range as to 
thickness. The richness of cream usually skimmed by separators 
ranges from 25 per cent to 50 per cent. Most separators, how- 
ever, will do good skimming even if the cream contains as high 
as 60 per cent fat. This, however, should be considered to be 
about the maximum, in order to get the best results from a sep- 
arator. 

Slush in Bowl. — As has been mentioned before, there is 
always a thick, slimy substance which adheres to the bowl-wall. 
The composition of separator-slime is, according to Fleischmann, 
as follows: 



166 SEPARATION OF CREAM 

Water 67.3 

Fat I.I 

Caseous matter 25.9 

Other organic substances 2.1 

Ash 3-6 



100. o 



At the center of the bowl, or along the perpendicular axis, 
there is always considerable cream. It is practically impossible 
to get all the cream out of the bowl, even if it is flushed with 
much water. The amount of slush varies somewhat with the 
different kinds of separators, and it is essential that this amount 
should be taken into consideration when the comparative 
skimming efficiency of different separators is considered. When 
the test extends over a comparatively long period, and the milk 
skimmed amounts to several thousand pounds, the bowl slush 
does not greatly affect the conditions for comparative results; 
but when the test is short, and only a hundred pounds of milk, or 
thereabout, is skimmed, the amount of fat left in the bowl-slush 
will have considerable influence upon the choice of a machine. 

General Remarks. — In order to keep the separator in good 
running order, it must receive care. The belt should neither be 
too tight, nor too loose. If too tight it is likely to bind, heat, 
and set the bearings of the separator. If too loose it is Hkely 
to slip, and to wear out more quickly. The machine should be 
well oiled. It is better to use a trifle too much oil than not 
enough. If a bearing is once heated, the machine will never 
run as well again. 

The bowl should be handled with great care. Bowls, or 
parts belonging to the bowl, can be kept from rusting by boiling 
them in water, or by steaming them thoroughly after they 
have been cleaned. If scalding-hot water is used before the milky 
portion has been washed off, the albuminoids will be scalded on 
to such a degree that it will be difficult to get them off. This 
applies to all dairy and creamery utensils. It is said that tin 
or ironware may be prevented from rusting by being dipped into 



CONDITIONS AFFECTING EFFICIENCY OF SEPARATORS 167 

hot water after washing. If the bowl, pail, or whatever utensil 
it may be, is turned over to drain after being dipped in hot water, 
the heat taken up by the utensil will in a short time perfectly 
dry the apparatus. If the bowl is steamed, it should be heated 
thoroughly to make it dry quickly. 

If the milk supply gets short during the run, and it is necessary 
to run the machine without feeding milk, the machine should 
always be flushed with lukewarm water. This will, in a measure, 
prevent clogging. Scalding-hot water should never be used for 
flushing the separator. The cream and skim-milk tubes should 
be carefully cleaned, with the special wire provided for that pur- 
pose, each time the machine is washed. The contrivances on the 
inside of the bowl should also be handled with care so as not to 
injure them in any way. They should be treated with hot water, 
as mentioned above, in order to keep them from rusting. 

When the bowl is not to be used for some time, it should be 
oiled well to prevent it from rusting. It is easier to oil a sepa- 
rator bowl than it is to scour the rust off later on. 



CHAPTER XIII 
FARM SEPARATORS 

The factors which influence the richness of cream are dealt 
with in Part II of the chapter on " Variation of Fat in Milk and 
Cream," while those affecting the efficiency of skimming are 
dealt with in the chapter on " Separation of Cream." These 
factors apply equally to power and farm separators. The con- 
ditions under which farm separators are operated warrant this 
separate chapter upon this subject. 

Introduction of Farm Separators. — Small, or hand, separators 
have been manufactured for a great many years, but their 
general adoption is of comparatively recent date. For instance, 
it was in 1894 — not so very long ago — that hand separators 
were introduced into the large dairy state of Iowa. Thirty years 
ago practically all of our creameries were milk-receiving cream- 
eries, while to-day the great bulk of our creamery butter is made 
from cream separated on the farm by means of hand or farm 
separators. Naturally the people of the Central West (Iowa, 
Kansas, Nebraska, Missouri, Minnesota, Illinois and Indiana) 
have been foremost in the development of this system, as it is 
best suited to their conditions. It permits many of the farmers 
who engage in dairying in a comparatively small way to become 
patrons of creameries located at considerable distances from 
them. 

Reasons for Introducing Farm Separators. — It requires an 
investment of about $100 to purchase a hand separator; it may 
therefore be concluded that some good reasons lead farmers to 
make such an investment. The chief of these may be briefly 
stated as follows: 

(i) The farmer is able to skim the milk immediately after it 
has been drawn, thereby enabling him to feed the milk while 

168 



REASONS FOR INTRODUCING FARM SEPARATORS 169 

it is in a warm, sweet, unadulterated condition. If he hauled 
the milk to the creamery, the skim-milk would be likely to come 
back in a sour and curdled condition, and at times watery. (In a 
well-conducted creamery these latter conditions do not exist.) 
(2) The high cost of hauKng in many instances makes it 




Fig. 51. — The Omega hand separator. 



almost impossible to get the milk to the creamery. Even if 
the roads are good, the distance to the creamery is frequently 
so great that it is impossible to get haulers, nor is it practicable 
for every farmer to haul his own milk every day. Especially 
is this so during the busy season of the year. In the fall, when 



170 



FARM SEPARATORS 



milk is scarce, it is almost impossible for the hauler to get enough 
milk to make it profitable. In many cases it is necessary to p^^y 
an excessive price for hauling milk. 

When cream routes are established instead of milk routes, 
one hauler can usually cover as much territory as three could 
under the milk system. Two thousand pounds of milk, testing 
4 per cent and containing 80 pounds of fat, would represent 

approximately a load of milk. At 25 
cents per 100 pounds, this would mean 
a cost of $5.00 for getting that much 
milk hauled. If the same amount of 
butter-fat were hauled in the form, of 
cream, it could be gathered for about 
3 cents per pound of fat, or the cost 
of hauling in this particular case would 
be $2.40. Under the milk system it 
would be necessary to haul the n' ilk 
to the creamery every day, while under 
the cream system it is usually gathered 
every other day in the summer, and 
every three days in the winter. It is 
usually considered that there is a saving 
of about 2 to 3 cents per pound of 
butter-fat in hauling, by making use 
of the cream system instead of the 
milk system. This, of course, would 
vary according to local conditions. 

3. The use of hand-separators makes farmers more inde- 
pendent than they are under the whole-milk system. They 
are not compelled to support their local creamery unless they 
deem it advisable. They can ship their cream to any place that 
they may choose. If the butter from the hand-separator cream 
is to be of as good quahty as that made by the whole-milk system, 
the cream should be delivered as often as possible. Every day is 
preferable to every other day. In case frequent delivery is made, 
it becomes quite essential for the farmer to patronize the local 
creamery, as very few farmers keep sufficient cows to get enough 




Fig. 52. — The De Laval hand 
separator (Baby No. i). 



OBJECTIONS TO FARM SEPARATORS 



171 



cream to pay them to ship by rail every day. Usually it does 
not cost much more to ship a can full of cream than it does to 
ship it half or three-quarters full. 

Objections to Farm Separators, — Under the present system 





Fig. 53. — Simplex hand separator and the different parts of bowl. 



of shipping cream long distances the quality of the butter made 
from it is often of a lower grade than that made from good whole 
milk. This is not due to any fault of the system, but to the poor 
care which the separator and cream may receive. The separator 
on the farm is sometimes kept in an unsuitable place, often in the 



172 



FARM SEPARATORS 



barn. If the milk is separated in such a place it will absorb odors 
and undesirable taints. The cream is not always taken care of 
properly after it is separated. The separators may not be 
cleaned well. A separator cannot be kept in good condition by 
simply flushing out the bowl with cold water at the end of each 
separation. It must be taken apart at the close of each skimming, 
and all the parts must be washed thoroughly in lukewarm water, 
and then scalded. The time and power required to skim the 




Fig. 54. — Sharpies separator and parts of bowl. 



milk and to care for the cream are in many instances regarded as 
objections to the system. 

Thickness of Cream. — Most butter-makers at central plants 
prefer cream containing about 30 to 40 per cent of fat. Such 
cream is not thick enough to cause any inconvenience in sampling 
and weighing. It can be diluted with a good starter and ripened 
without becoming so thin as to produce unfavorable conditions 
for churning. By some it is deemed advisable to skim even 
thicker than this, up to 50 per cent. Cream containing this much 
fat, however, is difficult to handle, especially during cold weather. 
It becomes so stiff that it is difficult to pour, and there is also 



THICKNESS OF CREAM 



173 



danger of losing more or less cream through its adhering to the 
sides of the cans. 

A thick cream is advisable from the farmer's standpoint. 





Fig. 55 . — Peerless hand separator and cross-section of bowl. 




Fig. s6. — Agos hand tester. 



The thicker the cream is, the more skim-milk he will retain on 
the farm for feeding purposes. It can also readily be seen 
that if thin cream is skimmed greater can capacity is necessary, 



174 



FARM SEPARATORS 



and the express charges will be heavier than if the thicker cream 
were skimmed. Rich cream does not sour so rapidly as does thin 
cream. 

The richness of cream can be readily ascertained by the use of 
a Babcock test, which every farmer should have in his possession. 
A whole outfit for testing fat in cream or milk can be had for 
about $10.00 from any creamery supply-house. By the use of 
such a test, the farmer can test his cream and skim-milk. He 
can also test the milk of each individual cow in the herd, thereby 
ascertaining which ones are profitable. By the use of such a test 
on the farm, the farmer can test his cream daily, and compare 




Fig. 57.— Tread-power attached to United States hand separator. 



results with those from the creamery, thereby enabhng him to 
detect any mistake which may happen at the creamery. 

Power for Farm Separators. — Hand-power is often men- 
tioned as an objection to farm separators. When a considerable 
quantity of milk is to be skimmed, it is certainly hard work to 
skim with hand-power. Windmills could not well be used as 
they do not give uniform speed. Tread-power is often used to 
run farm separators and is very well adapted to this purpose, as it 
is steady and uniform, and does not cost anything after the 
apparatus has once been purchased. The power can be supplied 
by using different kinds of animals; Sheep, goats, dogs, and 



POWER FOR FARM SEPARATORS 



175 




Fig. s8.— Showing the height to which cream free from air bubbles must be raised 
m a pipette to get 18 grams of cream. It shows that to measure cream in a 
pipette is inaccurate in cream testing. (Iowa State Dairy Com. Report, 1903.) 



176 FARM SEPARATORS 

bulls are used for this purpose. The process does not usually 
last very long, and the work is not considered heavy. Steam is 
good power, but it is hardly ever obtainable on the farm. 
Small gasoline-engines are also used very successfully. 

The machine should always run smoothly in order to get 
efficient skimming. It should never be stopped and started with 
a jerk. If it is started slowly there will be less danger of breaking 
any o^ the gearing parts. The bowl and inside parts should be 
kept from rusting as described previously on page 167. The 
bearings should be well oiled. It is a good plan to have an extra 
bearing or two on hand, so that if one happens to wear out 
another one can be put in. The bearings should be cleaned at 




Progeny of a 
single germ in © 
twelve hours 



Fig. 59. — Showing the effect of coohng milk on the growth of bacteria. The bene- 
ficial results of early chilling are readily apparent. (From Bui. 62, Wis.) 

intervals. When kerosene is occasionally used on the bearings 
they do not need to be cleaned so often, because it keeps them 
from gumming. The machine should be turned at the proper 
speed, as indicated in the directions. A thicker cream will 
result from rapid turning; consequently more skim-milk will be 
obtained. Slow turning causes inefficient skimming and thinner 
cream. 

Care of Cream on the Farm. — The first step in the production 
of good cream is clean milking. Thi&can be accomplished only 
when barn, cows, and utensils are clean. It is a good plan to 
dampen a cloth, and wipe off the cow's udder and sides previous 
to each milking. The milker should never wet his hands while 



CARE OF CREAM ON THE FARM 



177 



milking. Dust should not be stirred up in the barn during 
milking, as the dust particles carry with them a large number of 




Fig. 6o. — The condition of the cow shown in this cut is favorable for the accumu- 
lation of loose dirt. (Bui. 84, 111.) 



undesirable germs, and when these settle in milk they are likely 
to produce taints. If cloth strainers are used they should be kept 



178 



FARM SEPARATORS 



scrupulously clean. It is advisable not to use them at all, as 
good sanitary wire-gauze strainers are inexpensive. 




Fig. 6i. — A clean cow. The dirt cannot adhere to this cow to so great an extent 
as to the one shown in Fig. 60. (Bui. 84, 111.) 

If these conditions are complied with, and the separator 
is kept in a good clean condition, the milk will have compara- 



DISPOSITION OF THE CREAM 179 

tively few germs in it. Some germs, however, will enter the 
milk, and in order to keep them from developing, it is essential 
to cool the cream or milk immediately. Low temperature 
retards and practically prevents the development of germ life. 
It is a well-known fact that when milk is kept cool, it will remain 
sweet much longer than if kept at a high temperature. Two 
milkings or skimmings should never be mixed unless both are well 
cooled first. In order to cool cream quickly, it should be stirred 
during coohng. The ordinary four-gallon shot-gun cans are 
good and suitable for keeping milk and cream. They have 
a large cooKng surface in proportion to their cubical content. 
The milk or cream should be cooled as low as the water will 
cool it, and even lower than this if ice is obtainable. In keeping 
milk, the temperature should never go above 60° F. Cooling to 
50° F., if it can be accomplished, is much more desirable for 
keeping milk or cream in good condition. 

If considerable milk is handled, it is well to provide a milk- 
house. It should be built, large enough to contain the sepa- 
rator, water-tank, and other utensils necessary for home butter- 
making, such as a churn and butter- worker. There should be 
plenty of windows on all sides to give good ventilation. The 
water-tank should be connected directly with the well, so that 
the water can be pumped directly to the tank holding the milk 
and cream. From this place the water can be run out into the 
stock-tank. This arrangement allows the milk to be kept at 
the lowest possible temperature. 

It is just as essential to cool the milk during the winter as it is 
during the summer. By pumping water through this tank 
practically all the time, the water in the tank will be kept from 
freezing. It is well to keep the surface of the water higher 
than the surface of the milk in the can. This will prevent the 
milk from freezing so easily. If the cold is too severe, a tank- 
heater can easily be secured which wiU moderate the temperature 
a trifle. 

Disposition of the Cream. — There are two ways of disposing 
of cream on the farm: (i) selling it to creameries or other parties, 
and (2) making it into butter on the farm. The former method is 



180 



FARM SEPARATORS 



Msually the most advantageous. Creameries, as a rule, are 
better equipped to control the quality of butter. The price per 
pound of butter-fat is usually about 2 cents below " New York 
Extras." A few of the best creameries are able to pay more 
than that. 

Shipping of Cream. — If cream is sent or shipped to cream- 
eries and central plants, it is essential that it be delivered as 
frequently as possible, and that it be delivered in cans which 
will help keep it in good condition. If cream is to be hauled 
any great distance and exposed to the sun, it is advisable to use 
special jacketed cans, which retard the transmission of heat. 
It is a good plan to cover the cans with a wet sack or cloth during 
the summer, and the use of a dry sack on the outside in the winter 
often prevents the cream from freezing. 

Making Butter on the Farm. — If cream is kept in good condi- 
tion and proper skill is ap- 
plied, the best of butter can 
be made on the farm. The- 
oretically, better butter can 
be made on the farm than at 
the creamery, because all 
conditions can be controlled 
better. In the creameries 
one can of bad cream mixed 
with a quantity of good cream 
is likely to contaminate and 
injure the whole lot. The 
cream which is to be made 
into butter on the farm should 
not be over-ripened before 
it is churned. In creameries, 
starters are used to set up a 
quick and desirable fermentation in the cream; conditions are 
usually such on the farm that it is not convenient and practical 
to use a starter. It is very essential that the cream be cooled to 
a low temperature (50° F.) and left at this temperature for at 
least two hours before it is churned ; otherwise the butter is likely 




Fig. 62. — A barrel churn. 



MAKING BUTTER ON THE FARM 



181 




Fig. 63 . — Skinner butter- worker. 



to be greasy and salvy. Butter should be colored and salted 

to suit the market and 

season. About one-half to 

one ounce of salt to i pound 

of butter usually gives 

good results. 

If a local trade can be 

secured, it is not necessary 

to pack the butter into 

tubs. In this case it may 

be kept in earthen jars. 

If no local trade can be 

secured, and it is essential to ship the butter, 20- or 30-pound 

tubs should be used. If a 
good quality and constant 
supply of butter can be 
secured throughout the 
whole year, it is an easy 
matter to find an excellent 
market at hotels or good 
restaurants. (For a more 
detailed discussion of but- 
ter-making, see Chaps. 
XVIT and XVIII.) Putting 
up butter in prints and 

wrapping them in parchment paper which bears the maker's 

name usually increases its selling price. 




Fig. 64. — Wizard butter worker (Creamery 
Package Mfg. Co.) 



182 



FARM SEPARATORS 




CHAPTER XIV 
NEUTRALIZATION 

The " Neutralization " of Cream 

Neutralization. — The principle of neutralization is not a new 
one. Its application in the laboratory is practically as old as 
the science of chemistry, but its application to cream is compara- 
tively recent. 

The principle is easily explained and understood. In chem- 
istry there are two large classes of substances which are opposite 
to each other in action and have a strong affinity for each other, 
namely, bases (which include alkalies) and acids. A base and 
an acid, when brought together, react upon each other to form a 
new substance which is neither an acid nor an alkaH, and is 
called a salt. For example, when hydrochloric acid and caustic 
soda react upon each other common salt and water are formed, 
thus, 

HCl + NaOH = NaCl + H2O 

(Hydrochloric Acid) (Caustic Soda) (Common salt) (Water) 

Again, when either quicklime or slaked lime (hydrate of lime) 
reacts with hydrochloric acid they form calcium chloride, which 
is the salt commonly used for making the brine used in connec- 
tion with refrigerator systems, as it can be reduced to a very low 
temperature without freezing. 

CaO -I- 2HCI = CaCla + H2O 

(Quicklime) (Calcium chloride) 

or 

Ca(0H)2 + 2HCI = CaClo + 2H2O 

(Slaked lime) 

183 



184 NEUTRALIZATION 

A definite quantity of a given alkali will always neutralize a 
definite quantity of a given acid. To take a concrete example: 
If upon trial we find that it takes 8 c.c. of a certain alkali solution 
to neutralize lo c.c. of a given acid solution, subsequent trials 
will show that they always combine with or neutralize each other 
in exactly the same proportions. In a test of this kind we use 
an " indicator " to tell us when the solution tested changes from 
an acid to an alkah. If phenolphthalein be used it remains 
colorless so long as the medium is acid, but as soon as the acid is 
all neutralized and the liquid becomes alkaline to the slightest 
degree, this indicator turns red. Litmus shows blue when the 
medium is alkahne and red when it is acid. 

The principle of neutralization has been appHed in dairy 
work for many years, in the form of the different alkah tests used 
in cheese- and butter-making to determine the acidity of the milk 
or cream. The reagent used is an alkali solution of known 
strength, usually a caustic soda (NaOH) solution. 

Lloyd, an English chemist, made use of it in connection with 
his study of the principles and practice of Cheddar cheese- 
making about thirty years ago, and Mann introduced his test, 
which is still in quite common use, in 1890. The principle of 
these different tests is the same. It is only in the details that 
they differ. 

In these acidity tests the acidity of the milk or cream is 
reduced to the neutral point, or the point where the substance 
tested is neither acid nor alkaline. This is true and complete 
neutralization. 

" NEUTRALIZATION " OF CREAM FOR BUTTER-MAKING 

We now come to the use of the words "neutralization" and 
"neutralizer" in a new sense, in connection with cream. What 
is, in popular language, termed the "neutrahzation" of cream is, 
in reahty, merely a lowering or reduction of its acidity to a point 
at which the cream can be efficiently pasteurized, without causing 
an excessive loss of fat in the buttermilk. The substances most 
commonly used for the purpose of reducing the acidity are milk 



"NEUTRALIZATION" OF CREAM FOR BUTTER-MAKING 185 

of lime and soda ash. Neither of these alkalies should ever be 
used to reduce the acidity of cream to the neutral point, as in 
doing this there is grave danger of injuring the quality of the 
butter made from it. The necessity for reducing the acidity of 
cream came in with the general use of the little hand separator 
on the farm. The volume of cream thus produced was small; 
hence, the holding of cream at home until a sufi&cient volume 
was accumulated for delivery resulted, in many cases, in cream 
being delivered in a very sour condition, or in such a condition 
that it could not be pasteurized unless the acidity was reduced. 

There is some dispute as to who first used an alkali for reduc- 
ing the acidity of cream so that it could be efficiently pasteurized. 
We find that in 1896, Babcock and Russell of Wisconsin issued 
Bulletin No. 54 explaining the preparation and use of viscogen 
for the purpose of restoring cream for city trade to its natural 
consistency, as in the process of heating the lime salts are thrown 
down and the cream assumes a very thin appearance. Viscogen 
is composed of cane-sugar and lime. We are told that one 
creamery in particular used viscogen as a neutrahzer in sour 
cream at a very early date. 

As far back as 1901-02, one of the authors conducted exten- 
sive experiments in the use of alkalies of various kinds for 
reducing the acidity of cream; and in so far as he knows he was 
the first to take up experimental work in reducing the acidity of 
cream for butter-making. Some butter-manufacturing firms, as 
early as 1905, used a lime preparation in the commercial manu- 
facture of butter. Since then the practice has gradually grown 
until now it is very general. 

Why do we neutralize cream? The authors believe that there 
is an entirely satisfactory answer to this pertinent question and 
hope to be able to show that modern creamery conditions demand 
and fully justify neutraKzation. 

Butter, at best, is a perishable product — so much so that even 
butter of the best keeping quality must be placed in cold storage 
at a low temperature (close to 0° F.) if it is to be held any length 
of time and retain its good flavor. The souring or ripening of 
cream for butter-making has been practiced from time imme- 



186 NEUTRALIZATION 

morial. Many farmers' wives have become so proficient in the 
art of ripening cream and the making of butter that they have 
gained an enviable reputation in their own communities. The 
system of ripening or souring cream had been practiced by the 
home dairies for a long time before alkali tests were used. At 
this early date it was the custom to ripen or sour the cream until 
it assumed a thick, granular appearance and had a pleasant 
sour taste. The flavor that cream imparts to butter depends 
upon the kind of organisms that predominate in it. The observ- 
ance of sanitary methods on the part of the producer is con- 
ducive to the presence of the right species of bacteria in the 
cream. Cleanliness and sanitary methods should be observed 
by the makers, whether in the private dairy or in the factory. 
This is one of the first requisites of good butter-making; hence, 
all good butter-makers, whether in the private dairy or in the 
factory, observe cleanliness as a fast rule. Some butter-makers 
have gained national reputations by exhibiting butter in state and 
national butter contests, due to their ability to control the ripen- 
ing of cream, by using pure lactic acid cultures in ripening to a 
certain degree of acidity. One of the main causes of undesirable 
flavors in cream is neglect on the part of the producers to thor- 
oughly cleanse separators and other utensils that come in con- 
tact with the cream on the farm, thus allowing undesirable 
ferments to gain control. Another cause is neglect to cool cream, 
immediately after separation, to a low temperature. No time 
limit can be rightfully placed on the delivery of cream. Some 
patrons deliver cream once or twice a week, even during the 
summer, in such condition that the highest grade of butter can 
be manufactured from it, while others deliver cream daily and 
yet its flavor is such that it is impossible to make the finest 
quahty of butter from it. The quality of butter produced 
depends upon the condition of the cream when it enters the 
churn. The fact that cream may be high in acid when it reaches 
the creamery is not an indication that poor butter will be made 
from it. If the acidity of the cream is reduced so that the cream 
can be efficiently pasteurized, a pure lactic acid culture can be 
used again to ripen it, as only a small portion of the milk-sugar 



"NEUTRALIZATION" OF CREAM FOR BUTTER-MAKING 187 

has been converted into acid at the first souring. A great deal 
of cream arrives at the factories in too sour a condition to make 
good butter unless the acidity is reduced. Hence, we can see the 
necessity of using a harmless alkali for reducing the acidity. 

The introduction of the farm or hand separator has revolu- 
tionized the creamery business in America. While no reliable 
statistics are available as to the number of separators used among 
the dairymen of the country, it is estimated that 90 per cent of the 
butter produced in the creameries of the country is manufactured 
from hand separator cream. The principal reason for the gen- 
eral adoption of the hand separator on the farms by American 
dairymen was that they were always able to get sweet, warm 
skim-milk for feeding the young stock. When milk was sent to 
the creameries under the whole-milk system, it frequently hap- 
pened through delays and other causes that the skim-milk would 
be in a very bad condition for feeding purposes upon its return 
to the farm. In addition to this, the lower cost of getting butter- 
fat to the creamery in the form of cream greatly reduced the 
expense. A can of cream has concentrated in it the fat of pos- 
sibly ten or more cans of milk, and the cost per pound of fat for 
shipping a considerable distance is small. Consequently, there 
have been established large creameries equipped with the most 
modern machinery, not only for the manufacturing of butter 
but for utiHzing the by-products as well. In addition to this, 
many such concerns have cut out the middleman and thus 
reduced the expenses of selling. Moreover, when a large volume 
of business is conducted at one place, more skilled labor can be 
employed. These are some of the reasons why the large or 
centralized creamery has developed so rapidly. 

It has been estimated that 80 to 85 per cent of our butter is 
made from cream produced by farmers who are not dairymen 
in the full sense of that term. Dairying with them is a side line. 
Hence, the volume of cream produced is not sufficient to war- 
rant its delivery to the creamery or buying station daily or even 
every other day. This means that a large volume of the cream 
received at the central plant is sour to a greater or less degree, 
although its flavor may be quite clean. When such cream has 



188 NEUTRALIZATION 

been " neutralized " by milk of lime and pasteurized, it can be 
made into a very fine quality of butter. The president of a large 
creamery company, possibly the second largest manufacturer 
of creamery butter in this country, made a sworn statement that 
during the year 1920 they manufactured 27 milhon pounds of 
butter from cream that had been separated on the farms in 
various states and that 25 million pounds out of the 27 million 
pounds sold for extras or specials, some of it selling at a premium 
even above specials. All this butter was made from cream of 
which the acidity had been reduced by milk of lime. The fact 
that cream can be shipped a long distance has been the means of 
developing and stimulating dairying in sections of the country 
where there was not enough cream available to supply a local 
creamery. Where there is a sufficient volume of business to 
sustain a local creamery, and the same is rightly managed, no 
system will give greater returns to the producer. Whether a 
creamery is local or centralized, the same condition prevails. 

To make butter of the best keeping quahty it is necessary 
that the cream be pasteurized. Local creameries, as well as the 
large creameries, receive some very sour cream, but not usually 
in as great proportion. If such cream is to be pasteurized, it is 
essential that the acidity be reduced. Investigations conducted 
by the Dairy Division of the Federal Government and others 
have demonstrated that butter made from cream with a low 
acidity possesses better keeping qualities when placed in storage 
than butter made from cream having a high degree of acidity. 
Reducing the acidity of cream to the right point is a problem 
that necessitates intelligent care and an understanding of the 
effects of the use of an alkali. Cream that has been exceedingly 
high in acid, which has been reduced by limewater or some other 
harmless alkali substance, cannot be re-ripened with safety to 
the same degree of acidity as sweet cream that has never had its 
acidity reduced. Investigation has not revealed any satisfactory 
explanation of this fact. It would seem that the alkali used for 
reducing the acidity does not penetrate all the particles of cream, 
or, in other words, that the cream is not in a perfectly liquid 
condition. Some cream received at the factories is very sour 



"NEUTRALIZATION" OF CREAM FOR BUTTER-MAKING 189 

and lumpy. It may be that the solution used does not come in 
contact with the acid encased in the lumpy cream or particles 
of cream. 

To get the best results from neutralization, a large fore- 
warmer should be used and the cream heated to 85° to 90° F., 
and thoroughly mixed by keeping the coil moving before and 
while adding the neutralizer. The neutralizer should be dis- 
tributed as evenly as possible throughout the entire mass so 
that it will come in contact as far as possible with all particles of 
the cream. 

Butter made from high-acid cream, whether pasteurized or 
unpasteurized, has a tendency to develop a pronounced fishy 
flavor when placed in storage. It is difficult to pasteurize sour 
cream if its acidity has not been reduced, as the heat causes the 
cream to become stringy or ropy, due to the coagulation of the 
casein. This is particularly true with thin cream. If the acidity 
of cream is high and it is churned in this condition, without having 
the acidity reduced, butter, made from it will invariably be sour. 
This will not impair its food value nor will it make the butter 
injurious to health, but it will impair the flavor. Large classes 
of people in America and the European countries spread their 
bread with sour cream and regard it as a delicacy. The health- 
fulness of buttermilk, koumiss, and other fermented milks is 
well known. 

In investigations pursued in the laboratory of the American 
Association of Creamery Butter Manufacturers on the heavy 
losses of butter-fat in buttermilk, it was found that the fat- 
globules that escape in the churning process and pass off in the 
buttermilk are the small globules which are encased in the meshes 
of the casein. The precipitation of the casein by heat in the 
process of pasteurization, where the acidity of the cream has not 
been reduced, causes extreme losses in the buttermilk. In some 
instances as much as i or 2 per cent of fat is found in buttermilk 
made from such cream. Hence, the reduction of the acidity 
for pasteurization is a necessity from an economic standpoint, 
if for no other reason. 

Sour cream is a farm problem. Every creameryman would be 



190 NEUTRALIZATION 

pleased to get cream in such a sweet condition that it would not 
be necessary to reduce the acidity for pasteurization. The 
alkahes most commonly used for reducing the acidity of cream 
are limewater and soda ash. The authors have never recom- 
mended the use of any other substance than limewater or milk 
of lime. The amount of lime used in reducing the acidity, some- 
what less than one-tenth of i per cent, is so infinitesimal that 
it passes off in the buttermilk and has no effect upon the butter. 
The fat-globules of milk being coated with a film, the alkah 
solution used for reducing the acidity is mixed with the serum 
or the other component parts of cream rather than the butter-fat; 
hence, the small per cent of lime used practically all passes off 
with the buttermilk. 

Investigations pursued under the direction of one of the 
authors showed that butter made from cream of which the 
acidity had been reduced by milk of lime did not contain any 
more lime than butter made from whole milk to which no lime 
had been added, and contained less lime than a number of 
samples of dairy or farm butter. Investigations of this butter 
were made at the Universities of Wisconsin, Cornell and Purdue. 
The explanation of the higher percentage of lime in dairy butter 
may possibly be that the cream for the farm butter was churned 
at a higher temperature than the cream from which the butter in 
the creameries was made. Butter churned at a high temperature 
will invariably contain a high percentage of casein. In such 
butter the lime will be held between the meshes of the casein; 
hence the liigh percentage of lime found in dairy butter, where no 
lime had been added to the cream, was undoubtedly due to the 
high temperature at which the cream was churned. Butter 
made from cream which has been subjected to reduction of 
acidity and pasteurization seems to give good satisfaction in the 
markets. This is particularly true during the storage season. 
Such butter is then sought by dealers in storage butter, owing to 
its excellent keeping qualities. 

The use of limewater in milk is of long standing and well 
known. Lime is an essential constituent of dairy products. It 
is there to build the bones and to serve other essential physio- 



"NEUTRALIZATION" OF CREAM FOR BUTTER-MAKING 191 

logical purposes. Lack of lime causes not only rickets in the 
young, but also serious physiological disorders in the adult. 
Some physiologists urge the addition of lime to the diet. Its 
importance is thus expressed by Dr. Sherman of Columbia 
University • 

" Calcium is present in still greater abundance. Milk con- 
tains slightly more calciimi, volume for volume, than does lime 
water. As a rule the calcium content of the diet depends mainly 
upon the amount of milk consumed. In family dietaries where 
ordinary quantities of milk are used, the milk is apt to furnish 
about two-thirds of the total calcium of the diet. Without milk, 
it is unlikely that the diet will be as rich in calcium as is desirable 
either for the child or for the adult." 

In their recent Circular, No. ii, the United States Depart- 
ment of Agriculture and the United States Food Administration 
state their conception of the need of lime as follows : 

" Milk gives your children lime and other salts which they 
need. There must be plenty of lime in their food, for a great 
deal of it is needed for their bones and teeth and a little for their 
blood and all other parts of their bodies. Right food, not drugs, 
is what children need. Big boys and girls and grown people, 
as well as children, need lime, because the bones are constantly 
wearing away httle by little and must be replaced." 

Milk is the chief food for lime. It is much richer in it than 
other common foods. These lines stand for lime, the top one for 
the lime in a cup of milk, the others for the lime in a serving of 
some other foods. Notice how much more there is in milk than 
in the others." 

AMOUNT OF LIME IN 
I cup of milk 

^ cup of carrots 



2 slices of bread 



192 



NEUTRALIZATION 



THE PREPARATION AND USE OF LIME AS A NEUTRALIZER 

While there are other preparations, as those of the sodas, 
which are sometimes used for the neutraHzation of cream, the 
present discussion will be limited to the preparation and use of 
lime compounds as neutralizers. 

Before proceeding with this, however, the authors would 
digress a little to give the results of analyses made of different 
samples of hme in the laboratory of the American Association of 
Creamery Butter Manufacturers. Eleven samples of lime from 
various parts of the United States were analyzed to ascertain 
their fitness for reducing the acidity of cream. The solubihty 
of the Hmes in a 0.7 per cent lactic acid solution and their neu- 
tralizing power in terms of lactic acid were determined. The 
investigators were surprised to find that this amount of chemical 
work revealed very little more than was evident to the senses, 
aided by common sense. Here follow a few typical exhibits: 









Silica 


Volatile, 


Iron and 




Mag- 
nesium 
Oxide 




No. 


Kind 


Quality 


(Sand), 
Per 


Per 


Clay, 
Per 


Calcium 
Oxide 


Total 








Cent 


Cent 


Cent 






4 


Hydrated 


Good 


0.31 


11-45 


0.73 


88.60 





100.00 


II 


Quick 


Good 


0. 26 


4-75 


1.56 


93 40 





99-97 


6 


Quick 


Good 


0.36 


7.00 


1-25 


58.20 


33-54 


100.35 


3 


Quick 


Poor 


2.43 


1-35 


6.44 


55-40 


34-19 


99-81 



No. II is a high calcium lime. Nos. 3 and 6 are magnesian 
limes. Although the percentages of calcium in 11 and 3 differ 
widely, they both give good results in reducing acidity. Mag- 
nesia acts like lime and is not as much incHned as lime to flavor 
the butter. It has a greater neutralizing power than calcium. 
No. 3 contained too much siHca (sand), clay and iron. This 
was just as discernible by a physical inspection as by chemical 
analysis. The sand could be seen and felt and the clay made a 
granular yellow mixture. 

There are two forms of Kme that are used in the preparation 
of neutralizer, namely, quicklime in lump or in powder form, and 
hydrat^ lime, which is quicklime slaked by the lime-maker 



THE PREPARATION AND USE OF LIME AS A NEUTRALIZER 193 

instead of the user. As is shown below, it takes 74 pounds of 
completely hydrated lime to equal 56 pounds of quicklime for 
neutralizing purposes. Of course, the hydration is often only 
partial and then the difference is not so great. 

It is really a lime mixture in the form of milk of Hme, and not 
lime water, that is used, as lime is only soluble to a very small 
extent in water, and it would require too much of this to make its 
use practicable. 

Lime should be free of such impurities as sand, clay and iron, 
and the lime preparations offered by responsible firms for neu- 
tralizing purposes usually are. 

It is very important that the Hme mixture be properly pre- 
pared. Much more trouble arises from improper preparation 
than from defects in the lime itself. 

Quicklime is obtainable in powder form, packed in tin canis- 
ters. This form gives excellent satisfaction, as the quicklime is 
clean, uniform and free of waste material, and keeps until it is 
all used; whereas in lump lime there is considerable waste, 
through air slaking and the rejection of unsuitable lumps. 

A very suitable mixture is made up in the proportion of 17 
pounds of water to 3 pounds of quick lime. The water should he 
as near boiling as possible and the lime should be added to the water 
and not the water to the lime. The lime should be added in four 
installments instead of all at once, and the mixture stirred thor- 
oughly after each addition of lime. If properly prepared the 
mixture will be very smooth and free of visible lime particles. 
When cool, it may be tested by putting the hand or a smooth 
butter spade into it and withdrawing. If smooth, showing no 
lime particles, it is a good mixture; if it shows a very few par- 
ticles, it is fair; and if it shows many particles it is a poor mixture 
and is more Hkely to impart a limy taste than is a smooth mix- 
ture. A good mixture properly added to and mixed with the 
cream, and not in excess, is not nearly so likely to impart a limy 
taste to the butter. 

A mixture of 3 pounds of lime to 17 pounds of water is the 
same as 15 pounds of lime to 85 pounds of water, or a 15 per cent 
mixture. 



194 



NEUTRALIZATION 



Whether one proceeds scientifically or mechanically in the 
preparation of his lime mixture, his work is based upon the fol- 
lowing: 

Molecular weight of quicklirne, CaO, is 40+16 = 56. 
Molecular weight of hydra ted, Ca(0H)2, is 40+2(16 + 1) =74. 
Molecular weight of lactic acid, CsHeOs, is 

(3Xi2H6 + (3Xi6)=90. 

But the limes are bivalent. Hence 56 pounds of quickhme 
or 74 pounds of slaked lime will neutralize twice 90, or 180 pounds 
of lactic acid. 

Hence i pound of lactic acid is neutralized by y^^% = .3iii 
pound quicklime. 

It takes 2.074 pounds of a 15-per cent mixture of quicklime to 
supply .3111 pound of quicklime. Hence 2.074 pounds of the 
quicliiime mixture will neutralize i pound of lactic acid, or reduce 
the acidity of 1000 pounds of cream o.i per cent; and it is upon 
this figure, which is theoretically correct, that the following table 
is based: 

TO REDUCE THE ACIDITY OF CREAM TO .25 PER CENT 





Initial Acidity of Cream 


Cream 
(Pounds) 


•30 


.35 .40 .45 .50 .55 .60 .65 .70 .75 .80 .85 .90 .95 


Pounds of 15 Per Cent Lime Mixture Needed 


100 


.1 


.2 


•3 


•4 


■5 


.6 


•7 


.8 


■9 


1.0 


I.I 


1.2 


1-3 


1-5 


500 


■5 


1.0 


1.6 


2.1 


2.6 


31 


3 


6 


4.1 


4-7 


S-2 


S-7 


6.2 


6.7 


7-3 


1000 


I.O 


2.1 


3-1 


41 


5-2 


6.2 


7 


3 


8.3 


9-3 


10.4 


II. 4 


12. 413-4 


14-5 


1500 


i-S 


31 


4-7 


6.2 


7-8 9-3 


10 


9 


12.4 


14.0 


15.6 17.2 


18.7 20.2 


21.8 


2000 


2.1 


4.1 


6.2 


8.3 


10. 412. 5 14 


5 


16.6 18.7 20.7I22.8I24.9I27.0 


29.0 


2500 


2.6 


S-2 


7.8 


10.4 


13.0 15.6 18 


I 


20.7123.325.9128.531.1 


33-7 


36.3 


3000 


31 


6.2 


9-3 


12.4 


15.518.721 


8.24.9-28.0 


31-134-237-3 


40.4 


43-6 


3500 


3-6 


7.2 


10.9 


14-5 


18. I 21.8125 


4 


29.032.7 


36.3139.943.6 


47-2 


SO. 8 


4000 


4.1 


8.3 


12.4 


16.6 


20. 7 24.9,29 





33-237.4 


4I-5I45-749-853-9 


58-1 


4500 


4.6 


9-3 


14.0 


18.7 


23.3128.032 


7 


37-3i42.o 


46.751.356.0 


60.6 


65.3 


5000 


5-2 


10.4 


15-6 


20.7 


25-9 


3I-I 


36 


3 


41.5J46.7 


51.857.0,62.2 


67-4 


72.6 


5500 


S-7 


II. 4 


17.2 22.8 


28.5 


34-2 


39 


9 


4S-65I-3 57-062.7,68.4 


74.1 


79-9 


6000 


6.2 


12.4 


18.724.9 


311 


2,7-2, 


43 


6 


49.856.062.268.474.7 


80.9 


87.1 


6500 


6.7 


13s 


20.3 


27.0 


33-7 


40.4 


47 


2 


53.960.767.474.1 80.9 


87.6 


94-4 


7000 


7-3 


14-5 


21.8 


29.0 


36.3 


43-6 


5° 


8 


58.1165.472.679.987.1 

1 I 1 


94-4 


loi .6 



THE PREPARATION AND USE OF LIME AS A NEUTRALIZER 195 

The common practice in creamery work is to measure the 
lime mixture, in adding it to the cream, instead of weighing it. In 
case this is done the mixture should be made up so that there 
will be 12.5 pounds of quicklime in 10 gallons of the mix, that is, 
this quantity of lime should be mixed with about 8 gallons of hot 
water and then brought up to 10 gallons by adding sufficient hot 
water. This water to be added should be heated in an open vessel 
so as to drive off any carbom'c acid gas there may be in it, and 
should not be added directly from a hose or tap. 

In 10 gallons of the mixture there are 12.5 pounds lime. 

In I quart of the mixture there is — — = .3125 pound lime. 

40 

We have already shown that .3111 pound quicklime will 

reduce the acidity of 1000 pounds cream .1 per cent. Hence, i 

quart of the lime mixture, which contains .3125 pound quicklime, 

I "X^ '^ T 2 C 

will reduce the acidity of 1000 pounds cream ^ . =.1004 

.3111 

per cent = .1 per cent practically. Or, i pint of the lime mixture 

will reduce the acidity of 1000 pounds cream .05 per cent. It 

is upon these figures that the table on page 1 96 is based. 

How many pints of lime mixture will it take to reduce the 
acidity of 3400 pounds of cream from .70 to .25 per cent? In the 
column under .70 and opposite 3400, this is given as 30.5 pints. 
The same quantity of lime mixture would be used for all acidities 
nearer to .70 per cent than either .65 per cent or .75 per cent. 
This principle applies all through the table. 

Note the simple numbers opposite 1000 pounds of cream. 
The quantity of mixture required for any weight of cream can be 
quickly determined by multiplying the weight of cream by the 
amount of mixture required to reduce the acidity of 1000 pounds 
of cream to .25 per cent and dividing by 1000 (or pointing off 
three decimal places) . Example : 

How many pints of lime mixture will be required to reduce the 
acidity of 6300 pounds of cream from .80 per cent to .25 per cent? 

1000 pounds of cream require 1 1 pints of mixture. 

6300 pounds of cream require 11X6,300 = 69.3 = 69.5 pints of 
mixture. 



196 



NEUTRALIZATION 



PINTS OF LIME MIXTURE REQUIRED TO REDUCE ACIDITY TO 

.25 PER CENT 













Per Cent of Acid in 


Cream 










Lbs. of 












































Cream 


•30 


•35 


.40 


•45 


•50 


•55 


.60 


-65 


.70 


•75 


.80 


•85 


•90 


•95 


1. 00 


ICX) 






• 5 


•5 


•5 


•5 


•5 


I.O 


1 .0 


I.O 


I.O 


I.O 


1-5 


1-5 


1-5 


200 




•5 


■5 


I.O 


I.O 


1 .0 


1-5 


I-S 


2.0 


2.0 


2.0 


2-5 


2-5 


3-0 


30 


300 


• 5 


■5 


I.O 


I.O 


1-5 


2.0 


2.0 


2-5 


2-5 


30 


3-5 


3-5 


4.0 


4.0 


4-5 


400 


■5 


I.O 


1 .0 


1-5 


2.0 


2-5 


30 


3-0 


3-5 


4.0 


4-5 


5-0 


5-0 


5-5 


6.0 


500 


■5 


I.O 


1-5 


2.0 


2-5 


30 


3-5 


4.0 


4-5 


5-0 


5-5 


6.0 


6.5 


7.0 


7-5 


600 


•5 


I.O 


2.0 


2-5 


30 


3-5 


4.0 


5-0 


5-5 


6.0 


6.5 


7.0 


8.0 


8.5 


9.0 


700 


■ 5 


1-5 


2.0 


30 


3-5 


4.0 


5-0 


5-5 


6.5 


7.0 


7-5 


8.5 


9.0 


10. 


10. S 


800 


I.O 


i-S 


2-5 


30 


4.0 


S-o 


5-5 


6.5 


7.0 


8.0 


9.0 


9-5 


10.5 


II. 


12.0 


goo 


I.O 


2.0 


2-5 


3-5 


4-5 


5-5 


6.5 


7.0 


8.0 


9.0 


10. 


II. 


II -5 


12.5 


13-5 


1000 


1.0 


2.0 


30 


4.0 


50 


6.0 


7-0 


8.0 


9.0 


10. 


II. 


12.0 


13-0 


14.0 


15-0 


1 100 


I.O 


2.0 


35 


4-5 


5-5 


6.5 


7-5 


9.0 


10. 


II. 


12.0 


130 


14-5 


15-5 


16.5 


1200 


I.O 


2-5 


3-5 


5-0 


6.0 


7.0 


8.5 


9-5 


II .0 


12.0 


13.0 


14-5 


15 -5 


17.0 


18.0 


1300 


1-5 


2-5 


4.0 


50 


6.5 


8.0 


9.0 


10.5 


"■5 


13.0 


14-5 


155 


170 


18.0 


19-5 


1400 


1-5 


30 


4.0 


5-5 


7.0 


8.5 


10. 


II. 


12.5 


14.0 


15-5 


17-0 


18.0 


195 


21.0 


1500 


1-5 


30 


4-5 


6.0 


7-5 


9.0 


IO-5 


12.0 


13 -5 


15 


16. 5 


18.0 


19-5 


21.0 


22.5 


1600 


1-5 


30 


5-0 


6.5 


8.0 


95 


II. 


13.0 


145 


16.0 


17-5 


19.0 


21.0 


22.5 


24.0 


1700 


i-S 


3-5 


5-0 


7.0 


8.5 


10. 


12.0 


13-5 


15-5 


17.0 


18.5 


20.5 


22.0 


24.0 


25-5 


1800 


2.0 


3-5 


5-5 


7.0 


9.0 


II. 


12.5 


14-5 


16.0 


18.0 


20.0 


21-5 


235 


25.0 


27.0 


1900 


2.0 


4.0 


5-5 


7-5 


9-5 


II-5 


13-5 


15-0 


17.0 


19.0 


21.0 


23-0 


24.5 


26.5 


28. 5 


2000 


2.0 


4.0 


6.0 


8.0 


10. 


12.0 


14.0 


16.0 


18.0 


20. c 


22.0 


24.0 


26.0 


28.0 


30.0 


2100 


2.0 


4.0 


6.5 


8.5 


IO-5 


12.5 


14-5 


17.0 


19.0 


21.0 


23.0 


25-0 


27-5 


295 


31-5 


2200 


2.0 


4-5 


6.5 


9.0 


II. 


13.0 


15-5 


17.5 


20.0 


22.0 


24.0 


26.5 


28. s 


31.0 


33 


2300 


2-5 


4-S 


7.0 


9.0 


ii-S 


14.0 


16.0 


18.5 


20.5 


23.0 


25.5 


27-5 


30.0 


32.0 


34-5 


2400 


2-5 


5-0 


7.0 


9-5 


12.0 


14-5 


17.0 


19.0 


21-5 


24.0 


26.5 


29.0 


3I.O 


33.5 


36.0 


2500 


2-5 


5-0 


7-5 


10. 


12.5 


15.0 


17-5 


20.0 


22.5 


25.0 


27-5 


30.0 


32.5 


350 


37-5 


2600 


2-5 


50 


8.0 


10 -5 


13.0 


15-5 


18.0 


21.0 


23 -5 


26.0 


28.5 


310 


34 -o 


36.5 


390 


2700 


2-5 


5-S 


8.0 


II. 


13-5 


16.0 


19.0 


21-5 


24-5 


27.0 


295 


32.5 


35-0 


38.0 


40.5 


2800 


30 


5-5 


8.5 


II. 


14.0 


17.0 


19-5 


22.5 


25.0 


28.0 


31.0 


33-5 


36.5 


390 


42.0 


2goo 


3-0 


6.0 


8.5 


II-5 


145 


17-5 


20.5 


23.0 


26.0 


29.0 


32.0 


35-0 


37-5 


40.5 


435 


3000 


30 


6.0 


9.0 


12.0 


15.0 


18.0 


21.0 


24.0 


27.0 


30.0 


330 


36.0 


39.0 


42.0 


45-0 


3100 


30 


6.0 


9-5 


12.5 


15-5 


18.5 


21-5 


25.0 


28.0 


31.0 


34-0 


37-0 


40.5 


43-5 


46.5 


3200 


30 


6.5 


9-5 


13.0 


16.0 


19.0 


22.5 


25-5 


29.0 


32.0 


35-0 


38.5 


41-5 


45 -c 


48.0 


3300 


3-5 


6.5 


10. 


13.0 


16. 5 


20.0 


23.0 


26.5 


295 


330 


36.5 


39-5 


43-0 


46.0 


49-5 


3400 


3-5 


7.0 


10. 


13-5 


17.0 


20.5 


24.0 


27.0 


30.5 


34 


37-5 


41 -o 


44- 


47.5 


510 


3500 


3-5 


7.0 


IO-5 


14.0 


17.5 


21.0 


24. s 


28.0 


31-5 


35 -o 


38.5 


42.0 


45.5 


49 -o 


52.5 


3600 


3-'; 


7.0 


II. 


14.5 


18.0 


21-5 


25.0 


29.0 


32.5 


36.0 


39-5 


43 -o 


47-c 


50.5 


54-0 


3700 


3-5 


7-5 


II. 


15-0 


18.5 


22.0 


26.0 


29-5i33-5 


37 -o 


40.5 


44-5 


48.0 


52.0 


55-5 


3800 


4.0 


7-5 


II. 5 


15.0 


19.0 


23.0 


26.5 


30.534-0 


38.0 


42.0 


45-5 


49-5 


53.0 


57.0 


3900 


4.0 


8.0 


"•5 


155 


19.5 


23-5 


27-5 


31 .o35;.o 


39 


43 


47-0 


50.5 


54.5 


58.5 


4000 


4.0 


8.0 


12.0 


16.0 


20.0 


24.0 


28.0 


32.0:36.0 


40.0 


440 


48.0 


52.0 


56.0 


60.0 


4100 


4.0 


8.0 


12.5 


16.5 


20.5 


24-5 


28.5 


33 -o 


37-0 


41.0 


45 -o 


49 -o 


53-5 


57-5 


61. s 


4200 


4.0 


8.5 


12.5 


17.0 


21.0 


25.0 


29-5 


33-5 


38.0 


42.0 


46.0 


50.5 


54-5 


59 -o 


63.0 


4300 


4-5 


8.5 


13-0 


17.0 


21-5 


26. c 


30.0 


34-5 


38.5 


43 -o 


47-5 


51-5 


56.0 


60.0 


64-5 


4400 


4-5 


9.0 


13.0 


17-5 


22.0 


26.5 


310 


35 -o 


39-5 


44- 


48.5 


53 • 


57.0 


61.5 


66.0 


4=; 00 


4-.S 


9.0 


13-5 


18.0 


22.5 


27.0 


31-5 


36.0 


40.5 


45-0 


49-5 


54 -o 


58.5 


63.0 


67-5 


4600 


4-5 


9.C 


14.0 


18. 5 


23.0 


27-5 


32.0 


37.0 


41-5 


46.0 


50.5 


550 


60.0 


64- 5 


69.0 


4700 


4-5 


9-5 


14.0 


19.0 


23-5 


28.0 


33 


37.5 


42.5 


47 -o 


51-5 


56.5 


61.0 


66.0 


70.5 


4800 


5-0 


9-5 


14-5 


19.0 


24.0 


29.0 


33-5 


38.5 


43 -o 


48.0 


53 -o 


57-5 


62.5 


67.0 


72.0 


4900 


5-0 


10. 


14-5 


19-5 


24-5 


29-5 


34-5 


39-0 


44.0 


49-0 


54-0 


59 -o 


63.5 


68,5 


73-5 


5000 


5-0 


10. 


150 


20.0 


25.0 


30.0 


35 -o 


40.0 


45-0 


50.0 


55-0 


60.0 


65.0 


70.0 


75-0 


6000 


6.0 


12.0 


18.0 


24.0 


30.0 


36.0 


42.0 


48.0 


54 -o 


60. 


66,0 


72.0 


78.0 


84.0 


90.0 



THE PREPARATION AND USE OF LIME AS A NEUTRALIZER 197 

This is a general solution which applies to any weight of 
cream. 

Where lime is completely slaked or hydrated it takes a little 
over 32 per cent more of it than of quicklime (74 pounds as against 
56 pounds) to m.ake the same strength of mixture. As the mix- 
ture upon which the table (p. 196) is based contains 12.5 pounds of 
quicklime to 10 gallons, it would require 16.5 pounds of hydrated 
lime to 10 gallons to make the same strength of mixture. If 
the Ume is only partially slaked it will, of course, take less than 
16.5 pounds. 

The quantities of lime indicated for making the mixture are 
theoretically correct, but the individual user will be obliged to 
determine by test whether the mixture is right in strength for his 
cream. It may be necessary to use a little more or a little less 
lime than indicated, in making the mixture, probably a little less 
if any change has to be made. If necessary, a slight change may 
be made in the strength of the mixture to avoid changing the 
table. 

In investigations conducted by Hunziker, in which he used 
the strength and quantity of lime mixture supposed to be suf- 
ficient to reduce the acidity of the cream to .25 per cent, he 
secured the following average results: 

Per Cent 

Initial acidity of cream 75 

Acidity three hrs. after neutralizing, pasteurizing and cooling. . 33 

In other words, whereas the acidity should have been reduced 
by .50 per cent (.75 — .25) it was only reduced by .42 per cent 
(.75 — .33). This means that (33 — 2 5)-;- 50 or 5% = 16 per cent 
of the neutrahzer was not used, or that this mixture would need 
to be strengthened to the extent of the addition of 1 5 to 20 per 
cent more Hme. 

On the other hand, Hunziker found that when enough lime 
mixture was added to a pure lactic acid solution to theoretically 
reduce its acidity to .25 per cent it actually did reduce it to this 
point. The conclusion he reached, through his investigations, 
was that some of the lime added to cream attaches itself to the 



198 NEUTRALIZATION 

casein and therefore all of it is not used up in the neutralization 
of the lactic acid in the cream. 

The strength of a milk of lime mixture can be increased in 
either of two ways, (a) through the use of a larger proportion of 
lime, (b) through the use of lime containing a larger proportion of 
magnesium oxide, which is stronger, pound for pound, than 
calcium oxide. 

When a lime mixture is made up in small quantities, a ten- 
gallon can will suffice for this purpose. But where larger quan- 
tities are required a cylinder-shaped tank similar to a starter 
tank, with an agitator in it, should be used. This can be of any 
suitable capacity, say loo to 200 gallons. A simple gage may be 
used for measuring the contents. The user must remember that 
he is dealing with a mixture and not a solution, and that not 
only must there be a thorough agitation at the time the mix- 
ture is made but this must be repeated, to a lesser degree, when- 
ever any of the mixture is used, as the lime settles. 

Although the best limics do not contain 100 per cent calcium 
oxide, they usually contain enough magnesium oxide, which is 
stronger pound for pound than calcium oxide, to make up for this 
shortage. 

There are some points that should be kept carefully in mind 
in the preparation and use of neutralizers. 

The lime does not act so quickly and completely that its full 
effect is secured immediately. For this and other reasons, the 
acidity of the cream after pasteurization is lower than it was 
before pasteurization. The amount of drop in acidity varies 
with the cream, lime mixture and locality. 

Some creameries add the hme mixture directly to the cans of 
cream. Some run it by a faucet into either the dump vat or the 
pasteurizer. Others fill a supply vat or forewarmer and then 
reduce the acidity to the desired point. The last method is the 
best. 

The authors believe there is yet considerable to be learned 
about methods of applying neutralizer to cream in order to 
secure the best results and avoid unnecessary losses of fat in the 
butteiTnilk. 



THE PREPARATION AND USE OF LIME AS A NEUTRALIZER 199 

A careful determination of the acidity of the cream should 
always be made both before adding the neutralizer and after it is 
pasteurized and cooled. It may be found necessary to reduce the 
acidity of the cream a httle more, or on the other hand it may be 
found that the acidity of the cream is being reduced too 
much. This determination will thus act as a guide for future 
work. 

If the cream is to be ripened again the acidity is usually 
reduced to 0.15 per cent to .22 per cent (9° to 12° Mann's) and 
then ripened to the desired acidity. 

Some prefer the use of slaked or hydrated lime. While hot 
water must be used in the preparation of the quicklime mixture, 
the hydrated lime should always be mixed with cold water. 

OTHER NEUTRALIZERS 

Some creameries use carbonate and bicarbonate of soda — 
commonly spoken of as soda ash — as neutralizers. The soda 
ash is very soluble in water and forms a clear liquid solution. 
This is more easily made and added to the cream than is the lime 
mixture, and doubtless this is the main reason for its use. 

What has already been said indicates the authors' preference 
for the use of lime as a neutrahzer and the reasons for this 
preference. The following points may therefore be treated 
briefly : 

Lime is something that is well known and generally regarded 
as clean and wholesome, and the use of it in the neutralization of 
cream will not offend, in the shghtest degree, the susceptibilities 
of the most fastidious. 

Attention is frequently drawn, by physiologists, physicians 
and students of diet! tics, to the necessity for a liberal supply of 
lime in the diet of children and adults, and to the fact that in 
many foods there is a shortage of this constituent. 

Limewater is commonly used as an accessory to and a cor- 
rective of the foods of hospital patients and of children and 
infants. 

While it is true, as has already been pointed out, that the 



200 NEUTRALIZATION 

lime used in the cream passes off in the buttermilk, yet it is 
important that the consumer feel assured that the substance 
used as a neutralizer is something which is not foreign to milk, 
cream and butter and is wholesome, and to which no objection 
can be taken. 



CHAPTER XV 
PASTEURIZATION 

Definition.^ — As applied to butter-making and city milk, pas- 
teurization may be defined as a process of heating milk or cream 
to a temperature sufficiently high to destroy the great majority 
of the bacteria and other ferments contained therein and cooling 
it quickly to a low temperature. The name is derived from 
Louis Pasteur, an eminent French scientist, who made the dis- 
covery in the years 1860-64, that if wines were heated to a certain 
temperature (70° C. or 158° F.), and cooled again, fermentation 
would stop. 

In 1884 Soxhlet applied the method of heating to milk for 
destroying bacteria. 

Storch Test for Pasteurization. — Storch, at the Royal 
Agricultural Experiment Station, Copenhagen, Denmark, was 
the first to apply general pasteurization to cream for butter- 
making. Denmark has a law making pasteurization com- 
pulsory. This law was enacted to prevent the spread of tuber- 
culosis among the herds. The law requires that milk or cream 
must be heated to 80° C, or 176° F. Samples of skim-milk from 
the creameries are required to be sent to the Experiment Station 
where they are tested by the Storch test to ascertain if creameries 
are complying with the requirements of the law. 

Storch found that of all the reagents that might be used for 
determining whether milk or cream had been heated to 80° C. or 
176° F., the best was paraphenylene diamine. This compound 
ordinarily gives a brown color when acted upon by " active " 
oxygen, but in the presence of casein in milk the color is a beau- 
tiful indigo blue. 

To carry out the test about 5 c.c. of milk or cream are put 

201 



202 PASTEURIZATION 

into a test-tube and one or two drops of a 0.2 per cent solution of 
hydrogen peroxide is added from a dropping bottle, also two 
drops of a 2 per cent solution of paraphenylene diamine, from a 
dropping bottle. Brown dropping bottles should be used to 
prevent the light from weakening the reagents. The test-tube 
is then well shaken, and if the milk has not been heated above 
78° C, or 172° F., or if not heated at all, an intense blue coloration 
is produced. If at once or after half a minute the milk becomes 
bluish-grey, it indicates that it has been heated to a temperature 
of 78° C. to 80° C, or 172° F. to 176° F. When the color of the 
milk is unchanged after addition of the reagents, it may be 
concluded that the heating has exceeded 80° C. The blue color 
that develops on standing has no significance. 

Storch's test has shown itself to be the most reliable of all the 
methods proposed for distinguishing heated from unheated 
milk. All the so-called improvements which have been advo- 
cated by other chemists have proven to be of no benefit, often 
indeed the opposite. 

If during the pasteurization of the milk the temperature falls 
below 80° C. for a time, the whole of the milk after being mixed 
reacts to Storch's test. The sensibiHty of the test is so great 
that the admixture of 10 per cent of milk which has only been 
heated to 78° C, suffices to make the whole volume of milk react 
to the test. 

Pasteurization Temperatures. — In pasteurizing or heating 
milk for city trade or immediate consumption, low temperatures 
are used. This is done for the purpose of avoiding a cooked or 
heated taste. The method found most satisfactory for milk is 
to heat to 145° F., and hold at this temperature for twenty 
minutes. This is known to the trade as the holding method. 

Where the flash or instantaneous method is used, the milk or 
cream is heated to a temperature of 175° to 190° F. The tem- 
peratures most commonly used in butter-making in creameries 
are 180 to 185° F. Of late years the higher tem.peratures have 
been used for butter-making, even in the holding method. 

Marker, in the Canadian Northwest, recommends heating to 
170 or 175° F., and holding for fifteen or twenty minutes. This 



PASTEURIZATION TEMPERATURES 



203 



method of heating has been recommended by him for the pur- 
pose of destroying the enzyir.es in the cream. Butter made from 
cream thus treated has shown unusually good keeping qualities, 
and he reports that it does not go fishy when placed in storage. 
One of the advantages of pasteurization is that it destroys all the 
pathogenic micro-organisms in the cream if any be present. 
Efficient pasteurization destroys from 99.5 to 99.9 per cent of 
the organisms present in cream. Pasteurization, however, does 




Fig. 66. — The Simplex regenerative pasteurizer (apart). 

not put poor cream in a condition where good butter can be 
made from it. 

Pasteurization and sterilization are not the same. The 
latter means that milk or cream, or any other liquid substance, 
has been heated so often or to a high enough temperature to 
entirely destroy every living micro-organism present. In order 
to get a substance thoroughly sterilized without heating under 
pressure, it is essential that it be heated about thirty minutes 
on each of three or more consecutive days. 



204 PASTEURIZATION 

Good Milk and Cream Important. — The quality of butter 
made from pasteurized cream will depend to a very large extent 
upon the condition of the milk or cream used. If milk or cream 
is sweet and free from obnoxious flavors at the time of pas- 
teurization, the quahty of the butter made from it will be good, 
provided that the butter is not injured in the process of manu- 
facturing. The quahty of the cream used has a bearing not only 
upon the quahty of the butter made from pasteurized cream but 
upon that made from unpasteurized cream as well. 

The impression prevails to some extent that butter made 
from raw cream will not possess keeping qualities and that if 
placed in cold storage it will develop a fishy flavor. Investiga- 
tions pursued by one of the authors do not bear this out. In 
1907 he conducted a series of experiments at Strawberry Point 
Creamery, Strawberry Point, Iowa, during the month of July. 
This experiment was conducted under regular creamery con- 
ditions, and was carried on for a period of two weeks. Apparatus 
was moved from the Iowa Experiment Station for making com- 
plete analyses of the butter and records of everything pertaining 
to this work were kept. The Strawberry Point Creamery at this 
time was receiving about 50,000 pounds of milk daily. The milk 
was received from the patrons in cylinder-shaped 20-gallon cans. 
It was inspected at the wagons, and any milk found slightly sour 
or tainted was rejected. Power separators were used for sep- 
arating the cream from the milk, and the cream separated con- 
tained a high per cent of fat, the fat-content, after starters had 
been added, varying from 37 to 39 per cent. The cream used was 
in as perfect a condition as cream delivered for butter-making 
purposes can possibly be. Pure culture starters were used for 
souring or ripening it. About half the butter was made from 
unpasteurized cream, and the other half from pasteurized cream. 
In every case, two different churnings of butter were made 
from the same vat of cream, or the cream was divided so that two 
separate churnings were made. The full object of the experi- 
ment will be dealt with in another chapter. Two 60-pound tubs 
of butter were packed from each churning and shipped to Gude 
Bros., New York City. Each one of these tubs bore a special 



GOOD MILK AND CREAM IMPORTANT 205 

number. When the shipment of butter arrived in New York, 
half was to be sold in the open market and the other half placed 
in cold storage. Three 56-pound cubical boxes were also packed 
from each churning; one of these boxes was shipped to London, 
England, one to Liverpool and one to Manchester, for the pur- 
pose of having the best English experts score and criticize the 
butter. The butter sent to New York was scored before going 
into cold storage, and it was rescored when it came out of storage 
by Mr. P. H. Keiffer, who is generally recognized as an excep- 
tionally good judge of butter. One of the authors was present 
in New York when this butter came out of storage. Strange to 
say, both the pasteurized and unpasteurized butter, after being 
in storage between six and seven months, came out of storage 
scoring as high as when they entered storage. Mr. Keiffer 
remarked that it was the finest lot of butter he had ever seen 
comie out of storage at that time. No difference was found in 
the English market between the scores of the pasteurized and the 
unpasteurized product. One of the English judges scored some 
of this butter 100, or perfect. Hence, its excellent quality, 
whether pasteurized or unpasteurized, was due to the quality of 
the raw material used. 

Cream of the character mentioned above is not available in the 
average creamery. Many investigations have demonstrated 
that pasteurization does produce butter of excellent keeping 
quality. In addition to this, it entirely eliminates the danger of 
transmitting disease to human beings or to animals. Veteri- 
narians and scientists seem to be divided in opinion as to whether 
bovine tubercle bacilli can be transmitted to human beings, 
but the fact that tubercle bacilli have been found in a vigorous 
condition in butter has a tendency to create a fear in the minds of 
som.e people that such a danger exists. For this reason alone, 
if for no other, cream should be universally pasteurized for butter- 
making, especially in creameries where facilities are available 
for doing work of this kind. Pasteurization gives the man- 
ufacturer better control of the cream so that a more uniform 
quality of butter can be manufactured. The wide adoption 
of pasteurization in this and other countries, and the fact that 



206 



PASTEURIZATION 



almost every city of any size requires it would seem to indicate 
that it should be made compulsory. Since the hand cream sep- 
arator has been generally adopted on the farm, pasteurization 
seems more necessary than before, as the washing and cleansing 
of all dairy utensils, including the separator, is left to the farmers, 
and it is only reasonable to suppose that some of them are care- 
less. Hence, we can see the necessity for pasteurization from a 
hygienic standpoint if from no other. 




Fig. 67. — The Simplex regenerative 
pasteurizer (assembled). 



Fig. 68. — ^The Jensen pasteurizer. 



Sanitation Must Accompany Pasteurization. — The chemical 
and bacteriological laboratory of the American Association of 
Creamery Butter Manufacturers analyzes, chemically and bac- 
teriologically, samples of butter sent in by members. Thousands 
of analyses are made during the year. It is found that the butter 
that contains the lowest counts of yeasts and molds is invariably 
produced in the best creameries. Certain species of bacteria, 



SANITATION MUST ACCOMPANYPASTEURIZATION 207 

yeasts and molds are present in almost all hand separator cream 
and cause the deterioration of butter in storage; the elimination 
of these micro-organisms retards such deterioration. Milk or 
cream that is efficiently pasteurized will contain neither yeasts 
nor molds. In laboratory work conducted by the Association, 
butter in which the combined count falls below ten yeasts and 
molds in i c.c. of butter is considered good; in some of the best 
creameries the combined count drops to five or below. There 
are other things that affect the count of yeasts and molds found 
in butter. Pasteurization of cream may be perfect, and yet the 
cream may pass through unsanitary pipes and again be inocu- 
lated with yeasts or molds. Vats, faucets and churns are 
sources of contamination. Of the creameries sending butter to 
the Association laboratory, those whose butter shows the lowest 
count of yeasts and molds are creameries that are noted for 
observing extra precaution concerning sanitary methods in con- 
nection with all utensils that come in contact with cream. They 
use recording thermometers and automatic valves for regulating 
temperatures in pasteurization. The first cream passing through 
the pasteurizer is returned and reheated. Butter made in the 
creameries above-mentioned sells constantly at a premium. 
The quality of the cream received by them is no better than that 
received by other creameries operating in the same territory, 
which make very inferior butter. 

Pasteurization expels from the cream vapors and gases, 
especially carbon dioxide gas ; it removes volatile substances and 
flavors absorbed by the cream or milk. The heating causes the 
clusters of fat-globules to break up. Due to uniformity of 
quality and pasteurization, Denmark has been able to secure 
almost absolute control of the English market. Danish butter 
commonly sells at a premium over any other butter finding its 
way to that market, or at least it did prior to the war. 

One of the authors in discussing this subject with an English 
merchant, who handled a great deal of butter, asked for an 
explanation of the preference given to Danish butter. He 
answered that they occasionally got better butter from some 
other countries but that it did not run uniform in quality. He 



208 PASTEURIZATION 

said that the Danish butter was mild in flavor and uniform in 
quahty; in other words, it suited the trade and that was all that 
was wanted. 

Efficient pasteurization not only enables the manufacturer 
to make a more uniform grade of butter, but it makes the butter- 
milk safe to feed to live stock, thus preventing the spread of 
infectious diseases. It is said by some that if pasteurization were 
adopted more skill would be required on the part of the butter- 
maker. With valves for controlling the steam pressure and the 
use of recording thermometers, uniform pasteurization to any 
desired temperature can be brought about by a maker of ordinary 
skill, if he appHes judgment to the details of his creamery opera- 
tion. 

Methods of Pasteurization. — At the present time there are 
three methods of pasteurization employed for butter-making. 
The one most generally used is the flash or instantaneous heating 
method. Under this method the cream is heated to a high 
temperature, i8o° or 185° F., and quickly cooled, by passing 
over a cooler, to ripening temperature or to churning tempera- 
ture, as the case may be. In the vat, or holding, method cream 
is usually heated to a temperature of 150° to 160° F., held at 
this temperature for twenty to twenty-five minutes, and cooled 
to ripening or churning temperature. Some use the combined 
flash and holding method. 

Some of the best creameries that use the flash method, or high 
temperatures, follow what is known as the double system of 
pasteurizing. Two pasteurizers are attached to each other; 
the cream passes to the first pasteurizer from the forewarmer, 
where it is heated to a temperature of about 135° or 140° F. It 
passes from the first to the second pasteurizer where it is heated 
to 185° F., or any temperature desired. The live steam is con- 
nected with the second pasteurizer, and the exhaust steam from 
the second pasteurizer furnishes heat for heating the cream in 
the first pasteurizer to 140° F., or thereabout. The heating of 
the cream in the first pasteurizer increases the fluidity of the 
cream. Hence, when it enters the second pasteurizer, the heat 
comes in contact with all particles of the cream, and the efficiency 



METHODS OF PASTEURIZATION 209 

of pasteurization is thereby increased. From general observa- 
tion of work in many creameries belonging to the American 
Association of Creamery Butter Manufacturers, the authors 
feel safe in recommending this system. 

One of the authors first saw this system in general use at the 
Experiment Station at Kiel, Germany, something over twenty 
years ago. Dr. Weigman was heating to 190° F. at that time, 
and claimed very satisfactory results. 

The relative merits of the two systems — the vat system where 
the heating is done through a coil, or the use of a machine con- 
structed exclusively for pasteurizing milk and cream — depend 
largely upon local conditions. If the first cost only is taken 
into consideration, cream can be pasteurized more cheaply under 
the vat system, as the heating and the cooling are done in the 
same vat. In a small creamery where space has to be taken into 
consideration, the vat system is to be recommended. Not only 
does it require less space but it involves less labor. The objections 
to the vat system are, first, that the vat is not constructed for a 
pasteurizer, and, second, that the wear and tear (heating and 
cooHng, and expansion and contraction) will affect the life of 
the vat. These are items that must be taken into consideration 
when figuring the cost over a period of years. In a factory where 
a large volume of business is transacted, the regular pasteurizer 
would be preferable. It is much stronger than the vat and is 
constructed exclusively for the purpose of pasteurizing cream. 
In addition to this a greater amount of cream can be cared for in a 
shorter space of time. The cooling is done much more quickly 
where a regular cooler is used. Another advantage is that the 
heating and cooling are not done in the same vat, thus avoiding 
the expansion and contraction of the metals. 

Some use the method of heating in the flash pasteurizer and 
coohng in a vat. This does away with the necessity for a cooler, 
but, as stated above, the cooling is not done as rapidly as it would 
be if a regular cooler were used. This system works well where 
the holding system is practiced and lower temperatures are used 
for pasteurizing. Cream can be run into the ripening vat from 
the flash pasteurizer, held any desired time and cooled with a coil. 



210 PASTEURIZATION 

Under the regenerative principle the cold cream is heated 
by the hot cream passing from the pasteurizer. In the outflow, 
hot cream is cooled by the cold cream flowing into the pas- 
teurizer. The hot and cold cream then equalize their respective 
temperatures by passing in different directions. It is claimed by 
manufacturers of these pasteurizers that they effect a saving of 
25 per cent, or more. 

Most pasteurizers at the present time are constructed of 
heavy copper coated with tin. The heating surface of some of 
these pasteurizers is lined with German silver. From the stand- 
point of heat conductivity there is little choice between these two 
metals. It is a well-known fact that some metals will conduct 
heat better than others; the relative heat conductivities of 
copper and tin are .918 and .145 respectively. This means that 
copper will conduct heat nearly seven times as fast as tin of the 
same thickness, and therefore that copper might be seven times 
as thick as tin and still transmit as much heat as the tin. From 
this it can be seen that a heating wall made from copper can be 
increased slightly in thickness, and thus aid in stability, without 
affecting the degree of heat conductivity of the wall very much. 
The heating surface must be strong enough to withstand a 
slight steam pressure, otherwise the heating wall is likely to 
collapse or cave in, in case of slight variation in the steam pressure. 
It used to be a rather common occurrence for the heating walls of 
the pasteurizer to cave in or collapse in case of a slight variation 
in the steam pressure. This does not happen so often now. 

The condition of the cream has some bearing on the heating 
surface. Sour and coagulated cream burns and adheres to a 
greater extent than does sweet cream. This is evidently due to 
the lesser fluidity of the sour cream. Where two pasteurizers 
are used, this tendency is overcome to a very large extent. 

Efficiency of Pasteurizers. — Experiments conducted by Dr. 
Storch of the Royal Experiment Station, Copenhagen, Denmark, 
show that condensed steam offers great resistance to the trans- 
mission of heat. The comparative heat conductivities of water 
and copper are .0016 and .9 respectively, as found by Dr. Storch. 
It will thus be seen that copper is 600 times as good a conductor 



EFFICIENCY OF PASTEURIZERS 



211 



of heat as water is. This would mean that a quiet layer of water 
3 mm. in thickness would offer the same resistance to heat as a 
layer of copper 2 meters in thickness. Consequently a very 
thin layer of water or condensed steam on the sides of the heating 
wall would greatly interfere with the economic efficiency of a 
pasteurizer. 

In order to overcome this difficulty drip-rings were circled 




Fig. 69. — Jensen sanitaty pasteurizer-regenerator and cooler (Jensen 
Creamery Machinery Co.)- 



round the drum of the pasteurizer, at intervals, on the steam side 
of the heating surface. The first rings put around the pas- 
teurizer were narrow, smooth bands. These did not give entire 
satisfaction, as the condensed water from the top rings would 
drip on the edge of the lower ones, and cause the water to spatter 
over the side of the heating wall. Another kind of ring was then 
invented which was thin, narrow, and provided with teeth like 



212 



PASTEURIZATION 



those of a saw. The rings were fastened to the heating-wall at 
proper intervals at an angle of 45°. The rings were so arranged 
that the drops of condensed water escaping from the end of each 
saw-tooth would fall in the hollow between the teeth in the lower 
rings and thus prevent any spattering of the water against the 
heating wall. These contrivances greatly increased, the efh- 





FiG. 70. — Elyria pasteurizer (Elyria Enameled Products Co.). 

ciency — as much as 48 per cent — and the capacity of the pas- 
teurizer experimented with. 

Cost of Pasteurization. — Dr. Storch in his forty-third report 
at the Royal Experiment Station at Copenhagen, Denm^ark, 
reported that it required 80 pounds of steam to heat 1000 Danish 
pounds of milk from 40° C. to 85° C. This would be equivalent 



COST OF PASTEURIZATION 



213 



under American conditions to about 90 pounds of steam to pas- 
teurize 1000 pounds of milk from 90°F. toi85°F. 

According to good authorities, it takes about i pound of lump 
coal to produce 6 pounds of steam, although much depends upon 
the fireman and the construction of the boiler. Based upon 
this estimate, it would take 15 pounds of coal to produce 90 
pounds of steam. If the coal cost $4.00 per ton, the cost of 
the 15 pounds would be 3 cents. If the milk tested 3.6 per cent 
fat, the calculation upon one-sixth overrun of 1000 pounds of 
milk would produce 42 pounds of butter. The cost of pasteuriz- 
ing the milk producing 42 pounds of butter would then be 3 
cents, and the cost of pasteurization per pound of butter would be 
.07 of a cent. 

The figures submitted by Storch, however, were obtained a 
number of years ago, and cannot be applied to conditions in this 
country at the present time. 

Mortensen, who has given a good deal of thought to the cost 
under the continuous and vat methods, estimates as follows: 





Continuous 

Method, 

Cents 


Vat Method, 
Cents 


Cost of steam 


.019 
.009 
.181 


016 


Cost of water 


021 


Cost of labor and equipment 


•054 


Total 


.209 


.091 





The cost in different factories would vary with the cost of fuel. 
With the high railroad rates prevailing at the present time 
and the high price of labor, we can estimate the cost at about 
one-fifth of a cent per pound. 

In addition to this, the loss of fat in buttermilk seems to be a 
trifle more in pasteurized than in unpasteurized cream. This 
may be due to the precipitation of the casein by heat. Pas- 
teurization is necessary from a hygienic standpoint. It gives a 
guarantee to the consuming public that all pathogenic bacteria 



214 PASTEURIZATION 

are destroyed. It takes away from the enemies of butter the 
opportunity of proclaiming that disease may be transmitted to 
the human family through this article of diet. There is less 
danger of transmitting disease through butter than through any 
other dairy product. 

The senior author has been for more than thirty years engaged 
in the butter business in various capacities, from manufacturer to 
conductor of investigational work, and has never known of a 
case where any disease was transmitted through butter, from 
either pasteurized or raw cream. It has been demonstrated in 
all parts of the world that raw or unpasteurized milk will transmit 
bacillus typhosus. The first epidemic of typhoid fever which 
was traced to infected milk was one occurring at Penrith in 
1858 (Taylor). Since that time cases have become so numerous 
that almost all municipalities insist upon efficient pasteurization 
of milk. 

In addition to the effect that pasteurization may have on 
butter, pasteurization of the skim-milk and cream puts both the 
skim-milk and buttermilk in a condition where there is no danger 
of transmitting disease to animals. 

Disadvantages of Pasteurization. — The disadvantages of pas- 
teurization are, first, the cost of installing equipment, and, second, 
the additional cost of operation. Due to the increased cost of 
labor in recent years, it is difficult accurately to estimate the cost. 

Advantages of Pasteurization. — The advantages of pas- 
teurization far outweigh the disadvantages, and may be sum- 
marized as follows: 

(i) It destroys pathogenic bacteria if there be any present 
in milk and cream, and renders them and their products and by- 
products perfectly safe as foods. 

(2) It destroys practically all germ Hfe and enables the butter- 
maker to produce a more uniform quality of butter. 

(3) It is one of the large factors which improve the keeping 
quality of butter. 

(4) It eliminates some of the taints in cream. 



CHAPTER XVI 
CREAM-RIPENING AND STARTERS 

CREAM-RIPENING 

Definition. — By cream-ripening we mean the treatment 
cream receives from the time it is put into the ripening- vat until 
it is put into the churn; and also the chemical, biological, and 
physical changes it undergoes during this time. 

In the whole-milk creameries and in a few of the creameries 
receiving only cream, the cream goes into the ripening vat in the 
morning and no more is added during the day. In most cream- 
eries, however, cream is taken in throughout the day. This 
system does not permit of such perfect ripening of the cream; 
besides, it necessitates opening and closing the vat at intervals. 
Under this latter system it is important that the cream vat have a 
fly screen over it, and that one end of it be covered with a cream 
strainer through which all cream is strained before it enters the 
vat. 

Objects of Ripening. To Produce Flavor and Aroma. — 
The chief object of cream-ripening is to secure the desirable 
and delicate flavor and aroma which are so characteristic of good 
butter. The necessary flavoring substances, so far as known, 
can only be produced by a process of fermentation. Good butter 
possesses two characteristic flavors. One is known as palate 
flavor, or the distinctive butter flavor. The other is what is 
described by butter judges as a nose flavor or aroma, sometimes 
described as " bouquet " flavor. While the flavor and aroma 
characteristic of good, properly ripened cream and the butter 
made from it are produced by fermentation, the chemical changes 
that produce them are not well understood. It is claimed by 
some that the palate flavor is derived from the volatile fatty 

215 



216 



CREAM-RIPENING AND STARTERS 



acids, and the aroma from a fermentation of the milk-sugar. 
Good cream must possess a clean, pleasant, acid taste. For this 
reason, it is essential to have the' acid-producing germs predom- 
inate during cream-ripening. 

Butter has been made from sour cream from time immemorial. 
Housewives discovered a great many years ago that butter made 
from ripened cream had a more pronounced flavor and aroma 
than butter made from unripened cream. They also found 
that cream properly ripened would churn more easily and give a 




Fig. 71. — Projjress vat pasteurizer and cream-ripener. 
Da'rymens Mfg. Co.) 



(Davis- Watkins 



more exhaustive churning; hence, the practice of souring cream 
has been handed down to the creameries from the home dairies. 
Some women Ijecame noted for making butter of an exceptionally 
fine quality, because, in addition to observing cleanliness as the 
first requisite in making good butter, they selected nice, clean- 
flavored milk and let it sour naturally; this was added to the 
cream for the purpose of hastening the souring or ripening. 
Some of these dairies produced butter which was not only of good 
quality but also possessed good keeping quaHties. 

In the early days of butter-making it was customary for some 
to pack their butter in glazed crocks during the latter part of May 



CREAM-RIPENING 217 

or the first part of June, cover it with salt and hold it until the 
winter months, keeping it in the cellar or some other cool place 
until it was used up. As dairying advanced and butter began 
to be made on a large scale in creameries, in various countries, 
the bacteriologist resorted to the method of isolating certain 
species of bacteria for the purpose of ripening cream and pro- 
ducing the desired flavor. 

It has not yet been proved that any particular species of 
bacteria is responsible for the production of fine flavor in butter. 
It is generally agreed that the flavoring substances developed 
during the ripening of cream are decomposition products of bac- 




FiG. 72. — Wizard vat pasteurizer and cream-npener. (Creamery Package 

Mfg. Co.) 

terial growth, and it has been generally recognized that the types 
producing the lactic acid are the most desirable ones to have 
present in cream. There are a great many bacteria in milk and 
cream which produce acid, over one hundred species have been 
studied and described. It is apparent, however, that only a 
comparatively few of these produce the best results in cream- 
ripening. Hence, in the preparation of a natural starter, great 
care should be exercised in selecting milk that will sour with a 
pleasant acid taste. 

At the Iowa Experiment Station, McKay and Eckles con- 
ducted a series of tests on fermentation by taking milk from 
different patrons' herds, placing it in sterile glass bottles and 
allowing it to sour naturally. It was found that milk which 



218 CREAM-RIPENING AND STARTERS 

began to whey off at the bottom of the jar, soon after coagula- 
tion, due to certain species of bacteria decomposing the casein, 
invariably possessed an undesirable flavor. Samples of milk 
which would remain coagulated for some time and whey off at 
the top possessed a pleasant acid flavor. By selecting such 
samples of milk for preparing natural starters, these investi- 
gators were able to produce starters that gave excellent results 
in cream-ripening. 

Butter made at the school that scored the highest at one of 
the large national conventions, receiving a score of 98, was made 
from cream that had been ripened by a natural starter. The 
whole milk, received at the creamery when two days old, was 
skimmed so as to contain a very high per cent of milk-fat. The 
object was to concentrate the fat and get rid of as much of the 
skim-milk with its undesirable bacteria as possible, and then 
dilute the cream with fresh milk from the herds whose milk 
showed desirable results when souring naturally. The addition 
of a starter ripened naturally from the above-mentioned milk, 
ripened the ci eam which produced the high-scoring butter. 

Another test was made in a national contest where dif- 
ferent parties were placed in charge of the ripening, taking the 
entire milk as it came in on four different days, and the same 
method was followed with correspondingly favorable results. 
In this contest, in which about eight hundred creameries com- 
peted, the butter made by this method, on these four different 
days scored the highest, third, fourth and fifth in flavor. This is 
a further substantiation of what has been reported by various 
investigators, S torch. Conn and others, that the flavor developed 
depends very largely upon the species of germ life that predom- 
inate. 

Where cream has been pasteurized and inoculated with a 
starter containing the right organisms, the effects of the starter 
will be more pronounced than if the cream were manufactured 
raw or unpasteurized. This is due to the fact that the promis- 
cuous assortment of organisms in the natural bacterial flora is 
largely destroyed by the heating process in pasteurization. Bac- 
teriologists do not agree as to what species of bacteria is respon- 



CREAM-RIPENING 219 

sible for the high flavor and aroma of butter. Conn claims that 
the germs which act upon the nitrogenous matter of milk are 
associated with the lactic-acid-producing bacteria in the pro- 
duction of desirable butter flavors. Weigman asserts that 
the best results are obtained when a variety of species work 
together in the cream. He has isolated a single species of germ 
which produces alcohol and lactic acid as by-products, and which 
according to experimental evidence deduced by him, is capable 
of producing the delicate butter flavors. Freudenreich also 
studied a species of germ which produced alcohol and lactic acid 
as by-products, and which he claimed was able to produce the 




Fio. 73. — Cherry vat pasteurizer and cream-ripener. (J. G. Cherry Co.) 

characteristic butter flavors. Eckles studied the question of 
flavor production during cream-ripening. He came to the con- 
clusion that the flavor and aroma substances developed during 
cream-ripening may be produced by a variety of acid-producing 
bacteria. He asserts that of the species tried the most common 
milk-souring organism {Bacterium lactarii) gave the most satis- 
factory results as a culture for ripening cream. Storch, who has 
perhaps studied this question to as great an extent as any of the 
investigators, maintains that the germs producing lactic acid are 
essential to good cream-ripening, and that the flavor and aroma 
products are the results of the joint action of a great many 
species of lactic-acid-producing germs. Tiemann finds that an 
addition of a small amount of hydrochloric acid to the cream does 



220 



CREAM-RIPENING AND STARTERS 



not produce the characteristic flavor, and indicates that the 
process of fermentation is necessary to secure the proper flavors. 
The study, by Hammer and Bailey of the Iowa Station, of the 
causes of flavor and aroma development in cream-ripening is 
briefly outlined in the section of this chapter on " Starters." 




Fig. 74. — Vertical universal ripener and pasteurizer, vjensen Creamery 
Machinery Co.) 



This is probably the fullest investigation of this subject — in 
America at least — that has been conducted in recent years. 

Ripening Temperature of Cream. — In regular practice the 
ripening temperature of cream usually ranges between 60° and 
75° F. The lactic acid organisms and those associated with them 



CREAM RIPENING 221 

in a good starter have the greatest relative growth at 70° F., or a 
little above. Generally speaking, it is advisable to adopt a little 
lower ripening temperature in summer than in winter, For one 
thing, the cream has a tendency to rise a little in temperature in 
summer and to fall a little in winter, during the time of ripening; 
and furthermore, the natural bacterial flora present in summer are 
more favorable to cream-ripening than those present in winter. 
With the necessary modifications to meet conditions, 65° to 70° 
will be found a suitable range of temperature to adopt during the 
summer season and 70° to 74° during the fall and winter months. 
The amount of starter used and the length of the ripening period 
are factors that must be considered in deciding upon the tem- 
perature to be used. Where a fairly high ripening temperature 
is adopted a little greater precaution must be taken to prevent 
over-ripening of the cream, particularly if a liberal amount ot a 
good, active starter be used. 

Amount of Starter to Add to Cream. — The amount of starter 
to add, the ripening temperature and the length of the ripening 
period are related factors that influence each other. Also the 
richness of the cream places a limit upon the amount of starter 
that can be used. Generally speaking, where the separating is 
done on the farm the richness of a vat of cream is not so great as 
where the milk is delivered to and separated at the creamery, 
and consequently it is not practicable to use so high a per cent 
of starter in the former as in the latter case. The quantity of 
starter used will range from 10 to 20 per cent, depending upon the 
ripening temperature adopted, the richness of the cream, the time 
within which the ripening is to be done, and, to some extent, the 
cost of the milk or skim-milk used in making the starter. 

Mixing the Starter with the Cream. — When the starter is 
added to a vat of cream the coils should be run for a few 
minutes in order to mix the two very thoroughly. This is 
necessary to insure uniformity of ripening. 

Tests for Acidity. — The acid in cream is developed in the milk- 
serum, and the per cent of butter-fat that cream contains merely 
takes up space. Hence, in ripening cream some consideration 
should be given to the per cent of fat in it, as the fat is a neutral 



222 



CREAM-RIPENING AND STARTERS 



quantity. For instance, it is not safe to develop as high a per 
cent of acid in cream containing 40 per cent as could be devel- 
oped in cream containing 25 or 30 per cent of fat. For this and 
other reasons it is advisable to use a special test with which to 
measure the amount of acid developed in the cream. There are 
two acid tests in general use now in creameries, viz., " Mann's 
Test " and the " Farrington Test." 

Mann's Test. — Mann's test consists of measuring the acid in 




Fig. 75. — A creamery equipped with glass enameled tanks and vats. 



the cream by means of an alkali of a definite strength. The kind 
of alkali used is usually a tenth normal solution of caustic potash 
(KOH) or caustic soda (NaOH). These solutions can be made 
up very cheaply or bought from the supply houses. Mann's 
test is based upon measuring out 50 c.c. of cream by means of a 
pipette. While the test is based on 50 c.c. of cream a 25 c.c. 
pipette can be used, and the reading multiphed by two, thus 
avoiding the necessity of using so much cream. Even a smaller 
pipette could be used, but 25 c.c. is preferable to a smaller quan- 
tity, which would increase the danger of error. A few drops of an 



CREAM-RIPENING 



223 




indicator (phenolphthalein) are added. This indicator gives a 
red color in an alkaline solution, and no color in an acid solution. 
The tenth normal alkali solution is poured into a burette, and 
allowed to run into the 50 c.c. or 25 c.c. of cream (which is kept 
stirred thoroughly) until it begins to 
turn pink in color. At this point it is 
neutral. The number of cubic centi- 
meters of alkali required to neutralize 
the acid in 50 c.c. of cream indicates the 
number of degrees of acid. For in- 
stance, if it should require 32 c.c. of a 
tenth normal alkaH to neutralize the acid 
in 50 c.c. of cream, the acidity of the 
cream would be 32°. (i c.c. of N/io 
alkali = 1° Mann's Test.) 

Mann's test reading can be con- 
verted so as to express the results in 
percentage similar to the Farrington 
test. As I c.c. of the tenth normal 
alkali neutralizes .009 gram of pure lactic 
acid, 32 c.c, as in the above case, would 
neutralize 32 times .009. This would 
give the amount of acid, calculated in 
terms of lactic acid, present in the 50 c.c. 

of cream. This product divided by the 50, and multiplied by 
100, would give the percentage of the acid present. 

Farrington Test. — The same principle is involved in the Far- 
rington test. The alkali is put up in small tablets, already 
containing the indicator. These tablets contain a definite 
amount of alkaH, and are represented as retaining their strength. 
They lose it, however, if they are exposed to the atmosphere. The 
amount of alkali in each tablet is such that when five of them are 
put into a graduated cylinder, the cyHnder filled up with dis- 
tilled water to the 97 c.c. mark, and the tablets thoroughly 
dissolved in it, a solution is obtained, each cubic centimeter of 
which represents .01 of i per cent of acid, provided 17.6 c.c. of 
cream are taken. The tablets can be made up of different 



Fig. 76. — Apparatus for 
Mann's acid test. Instead 
of the burette the alkali 
can be kept in a large 
bottle, as shown in Figs. 
77 and 78. 



224 



CREAM-RIPENING AND STARTERS 



strengths for the use of different-sized pipettes, but as the 17.6 
c.c. pipette is the one which is used in the ordinary Babcock test, 
directions are given for the use of this pipette only. For a 
more detailed description of the acid tests see " Testing Milk and 
its Products," by Farrington and Woll. 

Degree of Acidity that Cream Should be Ripened to. — As to 





Fig. 77. — Arrangement for keep- 
ing alkali for the Mann's test. 



Fig. 78. 



the per cent of acid that should be developed in cream, this will 
depend upon such factors as the richness of the cream, the market 
demands as to fullness of flavor in the butter, whether the cream 
is sweet cream or cream that has previously soured and been 
neutrahzed, and the length of time the butter is likely to be held 
in storage. 



STARTERS 



225 



As has already been pointed out, rich cream should not show 
as high a per cent of acid when ripened as cream with a lower 
fat-content. If it should do so it is really a riper cream, that is, 
the skim-milk portion of it has been ripened to a higher degree 
of acidity. 

Where cream has soured and been neutralized before pas- 
teurization, it is advisable not to ripen to as high a degree of 
acidity as might be developed were the cream sweet to begin 




Fig. 79. — Apparatus for the Farrington acid test. 

with. Especially does this apply when butter is likely to be held 
any length of time. 

Unless market conditions demand it — and it is only in very 
exceptional cases that they do — it is not advisable to ripen 
average cream, or cream with a fat-content of about 30 per cent 
to an acidity of over .50 to .55 per cent. It is safer to err a trifle 
on the side of underripening rather than to overripen cream. 



STARTERS 



Definition. — By the term starter, in cream-ripening, we 
understand a medium containing a preponderance of desirable 
germs present in a vigorous condition. 



226 CREAM-RIPENING AND STARTERS 

History. — The use of starters in the dairy industry dates 
back a great many years. The fact that starters helped in the 
manufacture of dairy products was recognized years ago by 
practical men even before scientists recommended the use of 
pure cultures. In European dairy countries the use of the 
buttermilk borrowed from a neighboring factory to add to the 
cream in order to overcome abnormal conditions, was a common 
occurrence. In Holland, sour whey borrowed from some other 
factory was used to overcome gassy fermentation in cheese- 
making. While the reasons for this were not well understood, 
the underlying principle involved was that of overcoming the 
undesirable fermentation by adding ferments of an antagonistic 
kind. 

The introduction of commercial starters for cream-ripening 
dates back to 1890, when Professor Storch recommended their 
use in creameries in Denmark. After commercial starters had 
been used long enough in that country to demonstrate their 
worth, they were introduced into this as well as practically all 
the European countries, and are now used quite extensively. 

Classification of Starters. — Generally speaking, the different 
kinds of starters are included under the names (i) Natural, 
and (2) Commercial. The latter are prepared from a culture 
of bacteria obtained from the laboratory. The former, or nat- 
ural, include a great many kinds of dairy products which 
are supposed to contain a preponderance of those germs which 
are involved in the production of desirable flavors in butter. 
Buttermilk, sour cream, whey, and sour whole or skim-milk, 
are classed under this heading. While all these may be termed 
natural starters, and at certain times the use of any one of them 
may produce better results than if no starter at all were used, 
it is not safe to rely upon them to Turing about better results 
than could be obtained without the use of starters, because these 
products are likely to be contaminated in a large degree with 
undesirable germs. 

Preparation of Natural Starters. — The best natural starter 
is usually obtained by selecting a number of different samples 
of the best milk coming into the creamery and putting them 



STARTERS 227 

into cleaned sterile glass Jars. The samples are allowed to stand 
until sour at about 70° F. The sample which coagulates into a 
smooth uniform curd, and has a pleasant acid taste and smell is 
selected and used as a mother-starter. When a large quantity 
of selected pasteurized milk or skim-milk is inoculated with this 
and cooled to and held at a temperature of about 70° F., until it 
begins to coagulate, it will usually prove to be a starter which is 
equal, and often superior, to a commercial starter. 

Commercial Starters or Cultures. — Experiments have amply 
proved that certain species of bacteria are chiefly responsible 
for the butter flavors developed in cream during ripening. This 
fact has given rise to the use of cultures prepared in a commercial 
way. These cultures contain, in a vigorous condition, the germs 
which produce the desirable flavors and aroma. The cultures 
are put up in laboratories specially provided for this kind of work. 
Some of the laboratories put these cultures up in liquid form 
while others put them up in a dry or powder form. The liquid 
starters consist of a sterile nutrient medium, milk or beef broth, 
inoculated with the culture ; while the starters in dry or powder 
form are prepared by mixing the liquid culture with some suit- 
able substance, such as milk-sugar, and drying this mixture at a 
temperature low enough not to injure the germs present in it. 
The cultures that are put up in the Hquid form will not keep so 
long, and it is not safe to use them after they are about nine days 
old. The cultures which are put up in powder form have the 
advantage that they can be kept for a much longer time and still 
retain their vitaKty. Both kinds as a rule are good while they 
are fresh. We give a list on next page of the commercial cultures 
with which the authors are familiar. 

Technically speaking, most of the commercial cultures sent 
out from the different laboratories, to be used in the preparation 
of starters for milk- and cream-ripening, are not pure cultures of 
lactic acid organisms, although they are commonly spoken of as 
such. A pure culture is one which contains just a single species 
of organism, and most of these cultures contain more than one. 
The commercial cultures are, however, limited as to variety of 
species contained — usually two and at most three — and do not 



228 



CRKAM-RIPENING AND STARTERS 



contain a promiscuous variety of organisms. It is for this 
reason that they are commonly designated as pure cultures. 



Commtrciiil 
Starters 



Ameri- 
can 



Foreign 



S. C. Kcitli, 
Cliarlestown, 
Mass. 
O. Douglas, 
Boston, 
Mass, 
Elov Ericsson, 
St. Paul, 
Minn. 
Chr. Hansen's Lab- 
oratory, Little 
Falls, N. Y. 
Parke, Davis & Co., 
Detroit, 
Mich. 
Blaucnfeldt & 
Tvede, Copen- 
hagen, Den. 
Hjort & Fog's 
Laboratory Cul. 
Copenhagen, 
Den. 
S. P. Storm, 
Tillitze, Naks- 
kov, Den. 



Lactic Acid Culture 
Duplex Culture 
Boston Butter Culture 
Boston Butter Culture 
Duplex Culture 
Lactic Acid Culture 

Ericsson's Butter Cul- 
ture 



Liquid 



Licjuid 

Liquid 

and 
Powder 



Lactic Ferment Powder 

This culture is put 



Flavorone 



up in tablet and 
capsule forms 



Danish Lactic 
Acid Ferment 

Lactic 



Starter 



Powder 



Extensive work done by Hammer and Bailey of the Iowa 
Station not only supports what has just been said regarding 
commercial cultures, but also goes to prove that while the 
organism which predominates in a good culture or starter is the 
common lactic acid organism {Streptococcus laciicus), there 
must also be associated with this, an organism or organisms, 
which will develop volatile flavor and aroma-producing acids. 
Hammer says that it seems that there is no longer any question 
that starters are mixed cultures, and that even a pure lactic 
acid culture sent out from a laboratory very soon becomes a 
mixed culture containing volatile acid-producing organisms. 
These findings by Hammer and Bailey are supported by the work 
done by Storch in Denmark, and Beckout and Ott de Vries in 
Holland. 



STARTERS 229 

According to Hammer, the lactic acid, which is non-volatile, 
produces an acid flavor but very little of the flavor and aroma so 
characteristic of a good, well-ripened cream and the butter made 
from it. The organisms which he has found to be the most 
suitable associate organisms of the lactic acid organism {Strep- 
tococcus lacticus) are Streptococcus citrovorus and Streptococcus 
paracitrovorus. S. citrovorus acts upon the citric acid of milk 
and cream (hence its name) , and also to a certain extent upon the 
lactic acid, and converts these into volatile, flavor- and aroma- 
producing acids. S. paracitrovorus, in addition to performing 
the same function, also develops and uses another product. 

A good starter is one which will develop a fair proportion of 
the volatile, flavor- and aroma-producing acids without the 
development of an excess of acidity; that is, it will afford all the 
advantages to be gained from the proper ripening of cream without 
the disadvantages that come from ripening it to too high a degree 
of acidity. The great problem is that of the maintenance of a 
proper balance between the lactic acid organism (5. lacticus) and 
the associate organism or organisms which develop the volatile, 
flavor- and aroma-producing acids. One of the large factors in 
maintaining this balance is a proper ripening temperature in 
both starter- and cream-ripening. Hammer mentions 70-72° F. 
as a very favorable range. A temperature much above this is 
more favorable to 5. lacticus than to S. citrovorus, that is, it will 
enhance the development of lactic acid to a greater extent than 
that of the flavor- and aroma-producing acids, and throw the 
ripening out of balance. 

It would seem then that the big problem for our laboratories, 
in the preparation of commercial cultures, is to supply a culture 
which, if properly handled in the creamery, will develop a reason- 
able amount of suitable, volatile flavor- and aroma-producing 
acids without the development of excessive acidity in the cream ; 
and that one of the large problems for the creameryman is proper 
temperature control in both starter and cream-ripening, so as to 
enable flavor production to keep pace with lactic acid produc- 
tion. It would seem to be quite a safe practice to ripen the 
cream at a temperature of 70° F., provided care is taken to cool 



230 CREAM- RIPENING AND STARTERS 

it early enough to prevent the development of acidity from going 
too far. Under the varying conditions that exist in the dif- 
ferent creameries each creameryman will have to decide for 
himself the temperatures that best suit his conditions. What 
the authors have aimed to do is to state the underlying prin- 
ciples of successful starter and cream-ripening, and what they 
would urge most is the intelhgent application of these prin- 
ciples. 

Preparation of Commercial Starters. — All of the starters 
mentioned above have been tested and are known to produce 
good results. The first step in the preparation of a mother- 
starter (starterhne) is to prepare preferably a glass jar or bottle 
by thoroughly cleaning and sterilizing it. Glass jars are used in 
preference to any other vessel, because if they are unclean in any 
way, it will be apparent. Secondly, there are no seams and no 
places on the inside which will corrode, and in that way retain 
unnoticeable dirt; and in the third place, the nature of the coag- 
ulation can be readily observed through the glass. Mason jars 
and samphng bottles are suitable. The kind of bottle which 
is used for marketing milk gives very good results. 

The second step consists in selecting suitable milk. The 
milk must be in as pure and sweet a condition as possible. A 
good starter can be produced from either whole or skim-milk. 
At one time skim-milk was given a decided preference for use in 
the making of starters. But the views of some of our leading 
bacteriologists and practical creamerymen, experienced in the 
preparation and use of starters, have changed upon this point 
and they now express a decided preference for the use of whole 
milk starters. The reasons for this preference may be briefly 
stated: The whole milk is generally more easily selected; it 
is the practice in some of our best creameries to have some 
farmer supply milk, produced under special sanitary conditions 
and cooled promptly to a low temperature, for starter purposes. 
The trouble of separating and a possible extra source of contam- 
ination are avoided. The presence of the fat in the milk serves 
two useful purposes; first, the cream that rises seals the starter 
over and prevents contamination, and second, the exclusion of 



STARTERS 



231 



air prevents the development of certain injurious organisms, 
which may be present and which require air for growth. 

However, fine starters can be made from either whole milk or 
skim-milk, and the point of first importance is that the milk 
used be sweet and in a clean, sanitary condition. 

The milk which has been selected for the mother-starter, or 
starterline, is then pasteur- 
ized. The pasteurization is 
best accompUshed by the 
intermittent method. If 
considerable milk is to be 
pasteurized it is best to 
make use of a clean, steril- 
ized starter can. If only a 
small portion is to be pas- 
teurized, just enough for the 
mother-starter, the milk can 
be put directly into the jars. 
The jar half full is about the 
proper amount of milk to 
use. The directions sent 
with some pure cultures 
recommend as much as half 
a gallon or a whole gallon 
of milk. As a rule better 
results are obtained if only 
about a pint of milk is 
taken. If the milk for the 
mother-starter is pasteur- 
ized in the glass bottles 
or jars, it is advisable to set the bottles containing the milk 
into cold water, — covering the jar so as to prevent outside con- 
tamination, — and then heat up the water gradually. Care 
should be taken not to insert these bottles suddenly into scalding 
hot water, or to let the steam strike them, for either is likely to 
crack the bottles. Care should be taken also to exclude water 
from milk used for starters. It is advisable to heat this milk, for 




Fig. 8o. — An Incubating Chamber for 
Starters. The inner compartment will 
hold a pail of water and the bottles for 
the mother-starters. The temperature 
can be kept at any desired point by the 
use of warm or cold water. The four- 
inch space between the walls is filled with 
hay or mineral wool. (Dairy Bac- 
teriology, Russell and Hastings.) 



232 CREAM-RIPENING AND STARTERS 

the starterline, as high as possible in hot water, say up to about 
200° F. The sample may assume a cooked taste, but this will 
soon disappear after the starter has been carried on a few 
days. The milk should be left at this high temperature for 
about ten or fifteen minutes. A longer time does no harm. 
Then the milk is gradually cooled to about 80° F. This high 
temperature is desirable, because the germs present in the 
commercial culture may be somewhat dormant. This high 
temperature would tend to revive them more quickly than a 
lower temperature. Great care should always be taken to 
cool the milk previous to inoculating it with the pure culture, 
otherwise the germs present in the culture will be destroyed. 

Inoculation. — The next step is to inoculate the prepared 
milk with the culture obtained from the laboratory. The 
bottle which contains the culture is carefully opened, turned 
over and emptied into the pasteurized milk. It should be 
held down closely to the mouth of the jar containing the 
sterile milk, in order to prevent, as far as possible, the entrance 
of the air and the consequent danger of contamination. Then 
the milk containing the culture is thoroughly stirred and set 
away in a room where the temperature is about 70° F. This 
will gradually cool the milk from 80° to 70° F., and in about 
twenty to forty hours the milk will sour and coagulate. Germs 
in nearly all of the liquid cultures are rather slow in acting upon 
the milk, undoubtedly due to the dormancy of the germs, and to a 
comparatively few of them being present in the culture. When 
the powdered cultures are used, a little more care is essential to 
get the powder thoroughly mingled with the milk. It is a trifle 
more difficult to get the powder thoroughly mixed with the milk 
than it is to get the liquid cultures mixed. If anything is used 
with which to stir the sample, it should be sterilized before com- 
ing in contact with the milk. This applies in the preparation of 
all cultures. In testing or sampling the mother-starter, nothing 
should be allowed to come in contact with it unless it has pre- 
viously been thoroughly sterilized. The powder cultures are 
usually more vigorous in their ejffect than most of the liquid 
cultures now on the market. The powder cultures usually 



STARTERS 233 

coagulate the sample in about twenty-four hours, and if the 
operator is used to handling the liquid cultures, he should watch 
the mother-starters prepared from powder cultures, so that they 
do not get overripe. It is very essential that this should not 
happen. The tiine when the germs are most numerous and 
most active in the starter is about the time when the sample 
coagulates. As soon as this stage has been reached, or just 
previous to coagulation, the starter should be cooled down 
to at least 50° F., or lower if possible. This prevents any 
further growth of germs and the sample can thus be kept a short 
time without injury. 

Directions usually accompany each of the cultures, but the 
above will be found to produce good results with all of those 
mentioned in the above list. 

By putting from 2 per cent to 5 per cent or more of the 
mother-starter into a large sample of pasteurized milk, any 
desired amount of starter can be prepared. In selecting this 
amount of milk, as much care as possible should be taken in 
order to select the best kind of milk, and keep it from being con- 
taminated. When this large sample of starter is at the proper 
stage of coagulation, it should be used at once, or else cooled 
down to about 50° F. The amount of mother-starter with 
which to inoculate the large sample of starter may vary a Kttle 
without any bad effects. If the large sample of starter is to 
be ready for use in a short time, a larger portion of the mother- 
starter can be used for inoculation. If the temperature at 
which the starter is set and the amount of mother-starter used 
for inoculation are the same from day to day, the starter will 
be ripe at nearly the same hour every day, and, consequently, 
more uniform ripening results can be obtained. The noticeable 
coagulation of the starter when milk or skim-milk is used will 
usually take place when there is about .6 per cent of acidity. 
A slight coagulation will take place when there is about .5 per 
cent of acidity, but it is hardly noticeable. The coagulation- 
point may vary with different samples of milk. 

If a mother-starter is to be kept any length of time it should 
be inoculated into a sample of good fresh pasteurized milk about 



234 CREAM-RIPENING AND STARTERS 

every other day. If a mother-starter, or starter of any kind, 
is allowed to stand too long at a low temperature, the desirable 
germs will become dormant, and some undesirable germs will 
gradually gain a foothold. It is a good plan to carry any mother- 
starter along for two or three days before it is used to inoculate 
a large sample of milk. When the mother-starter is first pre- 
pared it sometimes possesses an undesirable taste and smell from 
the medium in which the germs were put up at the laboratory. 
This smell and taste are eliminated by carrying it on two or 
three days previous to its use. 

After inoculation and the proper mixing of the mother- 
culture with it, a new starter should not be disturbed during 
the ripening process. A good starter, when ready for use, will 
have a soft, close coagulation, without any gas openings or 
wheying off (particularly at the bottom); it will, when mixed, 
break up readily and form a smooth, creamy liquid entirely free 
of lumps, and will possess a pleasant acid taste and a character- 
istic aroma that is delicate and agreeable. 

It is of vital importance that a starter be prepared and kept 
in specially sanitary surroundings. While not absolutely essen- 
tial, it is advisable, if possible, to have a small room, suitably 
constructed and equipped, as a starter room. The chief equip- 
ment of such a room would consist of, 

(i) Quart sealers or bottles in which to prepare the mother- 
culture from day to day. 

(2) A small galvanized iron tank or box in which to sterilize 
bottles, thermometers, dippers, etc. It should have water 
and steam connections. 

(3) A small incubating chamber in which to keep the mother- 
starters. This is a small insulated box or chamber lined with 
galvanized iron and well insulated so that the temperature 
can be kept at any point desired. 

(4) A suitable starter can, one of suitable size, in which 
heating and cooling can be accomplished readily, and which is 
well insulated so as to hold temperature. 

One of our largest creamery companies, a company whose 
butter has won an enviable reputation in the New York and other 



STARTERS 235 

eastern markets, follows a system of handling and ripening 
cream, in all of its creameries, which is worthy of consideration. 
The acidity of the cream is reduced to about 15° Mann's Test 
(.27 per cent) for pasteurization, milk of lime being the neu- 
tralizer used. The cream is then pasteurized at a high tem- 
perature, 180° to 185° F., after which it is promptly cooled to 
ripening temperature. Before adding the starter the acidity 
is further reduced to 5° to 8°, Mann's (.09 to .14 per cent), 
if it has not already fallen to this during pasteurization. If 
there be any probability of trouble with metallic flavor the 
acidity is reduced still lower — to 2° or 3°, Mann's test (.04 or 
.05 per cent). A carefully prepared starter, which is active 
and possesses a desirable, clean flavor, is then added, and the 
cream is ripened and held overnight. The aim, in ripening 
the cream, is to develop an acidity of about 30° Mann's (.50 to 
.55 per cent) for churning. 

Great care is exercised in connection with the raw material 
and the preparation and use of the starter, and equal care is 
taken to avoid subsequent contamination of the cream, due to 
faulty or unclean pipes or utensils. As to the raw material for 
the starter, the practice is to arrange with some farmer to 
supply milk produced under special sanitary conditions, and 
promptly cooled and held at a low temperature until shipped. A 
special room is fitted up as a starter-room and this is placed in 
the charge of a man skilled in the preparation and use of starters. 

The butter made from cream, handled and ripened as indi- 
cated, possesses not only a fine, full flavor and aroma when 
made, but good keeping qualities as well. The butter made 
by this company commonly sells at a substantial premium over 
Extras and Specials. 

Milk Powder for Starters. — ^According to experiments con- 
ducted at the South Dakota Experiment Station, Bui. 123, 
milk powder solutions may be successfully used instead of the 
natural milk for starters. 

In many large central creameries, skim-milk is difficult to ob- 
tain. In such places milk powder can be and is successfully used. 

Milk powder is of about the same consistency as flour and 



236 CREAM-RIPENING AND STARTERS 

dissolves in cold water with similar difficulty. To make the 
milk powder dissolve as quickly as possible, weigh out the 
required amount of water into the starter can. Turn the steam 
on and heat. While the water is heating weigh out the required 
amount of milk powder. Use powder at the rate of 3 ounces to 
I quart of water. Add the milk powder to the water and stir 
violently. If little lumps remain stir every five or ten minutes 
during heating. Continue to heat or pasteurize as though it 
were normal milk. The remainder of the processes involved 
in making this into a starter are the same as already described. 

Length of Time a Starter Can be Carried. — In this country, 
even if special precautions are taken, it seems almost impossible 
to carry on a starter for more than four weeks without having 
undesirable ferments enter. The length of time a starter can be 
carried undoubtedly depends upon conditions, and the care 
with which it has been handled. When a starter is properly 
prepared, cooled gradually before coagulation, and not over- 
ripened, it will contain a smooth soft curd, and retain its mild 
acid flavor for. at least a month The Danes, who use starters in 
butter-making more regularly than any other people, are able to 
carry a starter along for six months or more without renewing it. 

It is a good plan to keep at least two different kinds of starter 
by carrying them on from day to day in small quart jars. Then if 
one should happen to " go off," the other one can be used instead. 

Poor Starters. — Many unsuccessful results from the use of 
starters for cream-ripening have been reported. The failure 
can be traced to the improper use of starters. If starters are 
good they will never bring about poorer results than are obtained 
without the use of them. Owing to the fact that it is difficult 
to keep the same starter in a good condition very long, many 
starters are used which develop abnormal fermentations in cream. 
A sHghtly acid, somewhat bitter taste, and a slimy condition of 
the starter are defects which are very common. These condi- 
tions seem to be brought about chiefly by overripening it at a 
high temperature, and keeping it a long time at a low tempera- 
ture before using it. Slimy fermentation is very common in 
starters which have been carried on for a time. Whenever this 



STARTERS 237 

slimy ferment develops in the starter it can be noticed both in 
the cream and in the starter by the failure of the acid to develop 
so rapidly as when the proper acid-producing ferment is present. 
It seems almost impossible to develop any more than about .5 
per cent of acidity in 30 per cent cream, while if the proper fer- 
ment were present, about .7 per cent could be developed. A 
decrease in the quality of butter accompanies the development 
of this ferment in the cream. 

Whenever it is found that a starter is not in good condition, 
it should not be used, as a poor starter is worse than none at all. 
The buttermilk from the previous cream can sometimes be used 
advantageously until a new starter can be prepared. 

Underripening and Overripening of Starters. — The effect of 
overripening starters has already been mentioned under the 
" Preparation of Mother-starters." The question of under- 
ripening starters is also of importance. It is a well-known fact 
that just about the time when the milk begins to turn sour, 
that is, when the sourness can just be recognized by the taste, 
it has a rather disagreeable flavor. After more acid develops 
the undesirable flavor largely disappears, and the milk assumes 
a clean, desirable acid taste. The reasons for this have been 
stated by Storch, the well-known authority on starters. He 
claims that this disagreeable flavor is due to the action of unde- 
sirable organisms, during the first souring stage. As the souring 
progresses these germs are subdued and gradually crowded out 
by the desirable acid-producing types. 

In the preparation of a starter the probabilities are that 
some of these undesirable types of germs are present. At least 
it is safer to go on the assumption that they are present. This 
makes the underripening of starters just as important to guard 
against as overripening. 

Amount of Starter to Use. — The amount of starter will vary 
under different conditions. It may vary from none at all to 
as much as 50 per cent of the cream to be ripened. The quality 
of cream is one of the factors that need to be considered. Raw 
cream and old cream both require a large starter, especially if 
the cream is thick enough to permit of being reduced in thick- 



238 



CREAM-RIPENING AND STARTERS 



ness. Good pasteurized cream does not need a larger starter 
than about lo per cent of the cream to be ripened. 

The amount of starter to use also depends somewhat upon 
the general creamery conditions. In some creameries all the 
cream is received in a very sour and poor condition, and facilities 
for getting milk for preparation of starters are often very poor. 
Under such conditions it is questionable whether it would be 
profitable to use starters at all. The amount of starter to use 
chiefly depends upon the degree of rapidity of ripening desired, 
and upon the temperature of the cream. If it is desirable to 
ripen quickly, a comparatively large amount of starter (15 per 
cent to 25 per cent) should be added, and the ripening tempera- 
ture should be comparatively high (about 70° to 74° F.) If slow 
ripening is desired, less starter may be used. Enough, however, 
should be used to control the fermentation in the cream (about 
10 per cent to 15 per cent), and the ripening temperature may be 

lower, between 60° and 70° F. More 
starter should be used in the winter. 
Use of Starter-cans. — In the past, 
ordinary tin shot-gun cans have been 
used in most cases for the prepara- 
tion of starters, and have given good 
results. Some makers still use such 
cans. 

The earliest starter-cans were 
made of light material and did not 
last long. These defects, however, 
have largely been done away with, 
and the use of starter-cans certainly 
is an improvement over the old 
method of preparing the starters in 
several smaller cans. 

These starter-cans are jacketed, 
so that the temperature can be con- 
trolled by using hot or cold water, or ice, as demanded, in 
the jacket. All of the starter-cans have an agitator, which is 
operated with a belt. 




Fig. 81 . — Improved Victor Starter 
Can. (Creamery Package Mfg. 
Co.) 



CHAPTER XVII 



CHURNING AND WASHING BUTTER 



Definition. — By churning we understand the agitation of 
cream to such an extent as to bring the fat-globules together 
into masses of butter of such size as to enable the maker to sep- 
arate them from the buttermilk. 

The agitation may be brought about in several different ways, 





Fig. 82. — Ancient method of churning 
in skin bags. 



Fig. 83. — ^The Dash churn. 



and by different shaped devices, which are called churns. The 
methods of churning, like the process of separation, began with 
primitive methods. The ancients churned their milk, without 
separation, in bags made from the skins of animals. The next 
step in advance was to place milk or cream in bottles or jars, and 
then to shake them. This latter method of churning cream in 
bottles is yet in use in many of the smaller households of Europe, 
where the amount of cream is limited to a small quantity donated 

2.39 



240 



CHURNING AND WASHING BUTTER 



by cow-owners. The next step toward churning on a large 
scale was to get a large wooden box or barrel run by power or by 
hand. The churns which are in use at the present time in 
American butter-factories are termed " combined churns." 
They are so arranged as to admit of churning, washing, salting, 
and working without removing the butter from the churn. This 
style of churn is now being introduced into Europe. Owing 
to their superior worth they will soon be in general use there as 
well as here. They keep flies away from the butter during fly 
time; the temperature of the butter can be controlled in the 
churn, and the handling of the butter during salting and working 
is obviated. 

CONDITIONS AFFECTING THE CHURNABILITY OF CREAM 

Temperature. — The temperature of cream is one of the most 
influential factors in determining its churnability. The higher 




Fig. 84. —Dual Churn (Creamery Package Mfg. Co.) 



the temperature of the cream, the sooner the churning process 
will be completed. Too high a churning temperature, however, 
is not desirable. It causes the butter to come in soft lumps 
instead of in a flaky granular form. This is deleterious to the 
quality of the butter. It causes, first, a greasy texture of the 
butter, and, second, the incorporation in the butter of too much 
buttermilk. This buttermilk contains sugar, curd, and water, 



CONDITIONS AFFECTING THE CHURNABILITY OF CREAM 241 



which, when present together in butter, are hkely to sour and in 
other ways injure the butter. Curd and sugar should be 
excluded from butter as much as possible, in order to eliminate 
food for bacteria which may be present. 
An excess of curd is also favorable to 
the formation of mottles.^ 

Too low a temperature is also un- 
desirable, although it is better to have 
the temperature a little low rather than 
too high. When the churning tempera- 
ture is too low, difficult churning is 
likely to occur. Cream at a low tem- 
perature becomes more viscous. On 
agitation in the churn such cream, if it is 

very thick, will adhere to the sides of the churn and rotate with it 
without agitating; consequently no churm'ng will take place. 
Too low a temperature brings the butter in such a firm condi- 
tion that it takes up salt with difficulty, and when this hard 




Fig. 85- 



Sectional view of 
Dual. 




Perfection Dreadnaught Churn (J. A. Cherry Co.) 



butter is being worked, a large portion of the water in the 
butter is expressed, and the overrun will be lessened to a great 
extent without increasing the commercial value of the butter. 

The degree of hardness of the fat in the cream is the govern- 
ing factor in deciding the churning temperature. The churning 
1 Bui. No. 263, Geneva, N. Y. 



242 



CHURNING AND WASHING BUTTER 



temperature will vary a great deal in different localities. The 
hardness of the fat depends upon (i) the season of the year; 
(2) the individuality of cow; (3) the stage of lactation; and (4) 
the kind of food fed to the cows. All these factors influence the 

melting-point of butter-fat. The 
higher the melting-point of the 
butter-fat is, the higher the churn- 
ing temperature, and the lower the 
melting-point of the fat, the lower 
the churning temperature. 

I. During the spring the cows 
yield milk containing a larger pro- 
portion of soft fats; consequently 
the churning temperature is always 
lower in the spring than in the fall 
or winter. During winter, when 
the cows are fed on dry food chiefly, 
the harder fats increase in quantity, and consequently a higher 
churning temperature is necessary during that time. 




Fig. 



87. — Sectional view of Perfec- 
tion working butter. 





Fig, 88.- Disbiow churn (Davis- Watkins Dairymen's Mfg. Co.) 



2. Some animals produce milk containing a larger propor- 
tion of softer fats than do other animals. It is said that the 
difference in this respect is more marked in certain breeds. It 
is maintained that the cows of the Jersey breed produce milk 




CONDITIONS AFFECTING THE CHURNABILITY OF CREAM 213 

containing a larger proportion of the softer fats than do those of 
any of the other breeds. 

3. The period of lactation also affects the melting-point of 
butter-fat. When a cow is fresh she yields a larger proportion 
of the soft fats than she does 
later on in the lactation period. 
Just how much this change in 
the hardness of the fat is due 
to advance in the lactation 
period and how much to 
change from succulent to dry 
feeds is not definitely known, 
since the two parallel each 
other so closely, it being the 
common practice in this coun- 
try to have the cows freshen . 

. Fig. 89. — Sectional view of Disbrow. 

m the spring. According to 

investigations conducted at the Purdue Station,^ the melting 
point of the fat lowers as a cow advances in her lactation period, 
provided she is fed the same feeds throughout the year. If 
these findings be correct, they mean that the influence of the 
feed is much greater than that of the stage of lactation, since the 
broad truth still remains, that under our conditions the propor- 
tion of hard fats increases as the lactation period advances. 
Witn this increase in the proportion of the hard fats in the 
advancement of the lactation period, the fat-globules become 
smaller. This, together with the increased hardness of the fat, 
causes difficult churning at times. It readily can be seen that 
the larger the fat-globules are the greater are the chances for 
these globules to strike each other during agitation in the churn- 
ing process. 

4. The nature of the food fed affects the melting-point of 
butter to a considerable extent. Cotton-seed and its by-products 
have been demonstrated thoroughly by several investigators to 
cause butter to become hard. When a large amount of cotton- 
seed is fed, the butter assumes a crumbly, tallowy, hard condi- 

^ Purdue Bulletin 159. 



244 



CHURKING AND WASHING BUTTER 



tion; while linseed meal, and practically all succulent foods, tend 
to decrease the melting-point of butter-fat. 

According to the above it can be concluded that the churning 




Fig. 90. — Master dual churn (Creamery Package Mfg. Co.) 



temperature may vary between wide limits, but the average 
desirable churning temperature under normal conditions is 
between 50° and 60° F. It may, and does, go outside these 

limits at times; for in- 
stance, many cream- 
eries find it necessary 
to churn at a tempera- 
ture under 50° F. in 
the early part of the 
summer season, when 
the grass is very young 
and succulent and the 
proportion of soft fats 
is very high. Any con- 
ditions which tend to 

Fig. 91. — Simplex churn (D. H. Burrell & Co.) ,11, r 

harden the butter-fat 
will require a comparatively high churning temperature; and 
any conditions tending to soften the butter-fat will require a 




CONDITIONS AFFECTING THE CHURNABILITY OF CREAM 245 

lowering of the churning temperature. The lower the tempera- 
ture at which the churning can be successfully accomplished, the 
more complete will be the churning; that is, the less fat will 
remain in the buttermilk. 

Influence of Length of Time Held at Churning Temperature. — 
The length of time that cream is held at the churning tempera- 
ture is a factor that must be considered. If it be found necessary 
to churn cream soon after coohng it, it should be cooled to a 
lower temperature than would otherwise be necessary. Cream 
should be held at least two hours at churning temperature before 
it is churned — better a longer time. It takes this length of time 
at least for the fat, which is a poor conductor of heat and firms 
slowly, to reach the temperature of the serum of the cream and 
become firm. 

In the same creamery, with cream of the same richness, we 
have observed that cream churned immediately after cooling 
would churn as readily at 51° to 52° F. as cream held at 56° F. 
overnight and churned without change of temperature. The 
per cent of fat was much lower in the buttermilk from the cream 
held overnight than it was in that from cream churned soon after 
being cooled. 

Richness of Cream. — The amount of fat in the cream affects 
the churnability of it considerably. The richer the cream the 
sooner will the churning be completed, that is, providing the 
cream is not rich enough to be so thick as to cause it to adhere 
to the inside of the churn and thus escape being agitated. If 
rich cream is churned at a high temperature the butter will come 
in a remarkably short time, providing all other conditions are 
favorable. Thin cream churns much more slowly, and can be 
churned at a higher tempera'ture than thick cream, without 
injuring the quality of the butter. When rich cream is churned 
at a high temperature, and the butter cqmes in a short time 
(about ten minutes), the butter will usually be greasy in body, 
and will contain a great deal of buttermilk, which will be more 
or less difficult to remove on washing. When thick cream is 
being churned, the butter does not break in the form of small 
round granules, as it does when thin cream is churned. 



246 



CHURNING AND WASHING BUTTER 



When thick cream is churned at as high a temperature as is 
consistent with getting a good texture, the best results are 
obtained. In the first place, rich cream produces less butter- 




FiG. 92. — Victor heavy duty churn (Creamery Package Mfg. Co.) 



milk, consequently less fat will be lost in the buttermilk. This 
would tend to increase the overrun. Secondly, the breaking 
of the butter at the end of the churning will be such as to cause 

the granules to appear large and flaky, 
rather than small and round. The 
more flaky granules of butter will 
retain more moisture than the smaller, 
harder granules under the same treat- 
ment. Experiments show that when 
different thicknesses of cream (thin 
cream containing on an average 22 per 
cent of fat, and thick cream 36 per 
cent of fat) are churned, there is a dif- 
ference of about 3 per cent in the mois- 
ture-content of the butter. The aver- 
age churning temperatures of cream and wash-water in these 
experiments were 56° and 53° F. respectively. 

When thick cream is churned, and the temperature is mod- 




FiG. 93. — Sectional view of 
four roll Victor working 
butter. 



CONDITIONS AFFECTING THE CHURNABILITY OF CREAM 247 

erately high, it is almost impossible to churn the butter into 
granules. This condition causes butter from thick cream to 
contain more moisture than butter from thin cream. 

Amount of Cream in Churn. — When the churn is about one- 
third full, the greatest degree of agitation is obtained, and con- 
sequently a quicker churning. If a small amount of cream is 
being churned, it is often difficult to gather the butter properly. 




Fig. 94. — Danish churns and frame for holding them. 



If the cream is thin, the granules are thrown about in such a 
way that they are gathered with difficulty. If the cream is 
thick, the small amount of cream will adhere to the inside of the 
churn, and in that way delay the completion of the churning. 
It is a common opinion that less overrun is obtained from 
a small churning than from a large churning. It is safe to say 
that if it were possible to maintain all conditions alike, especially 
as to temperature and degree of churning, there would be very 



248 CHURNING AND WASHING BUTTER 

little difference in the moisture-content of the butter made from 
churnings of different sizes. When there is only a small amount 
in the churn, the atmospheric temperature is likely to raise or 
lower the temperature of the cream. If the atmosphere is 
warm, then the butter from the small churning is more likely 
to be soft. A small amount of cream in the churn is also more 
likely to be overchurned than a larger amount of cream. These 
two factors would tend to increase the amount of water in the 
butter. In mixing the salt with a comparatively large amount 
of butter, less working is necessary. Much of the butter is 
mixed in the churn without going through the workers, and con- 
sequently less moisture will be expressed from the butter. With 
the same number of revolutions of the churn the butter from 
the small churning is worked correspondingly more than the 
butter from a larger churning. Medium firm butter, to a certain 
limit, loses about . 2 per cent of moisture for every revolution that 
it is overworked in the absence of water. 

Degree of Ripeness. — The riper the cream is, all other con- 
ditions being the same, the easier it will churn. Sweet cream 
is viscous, and consequently the fat-globules will not unite as 
readily. The acid developed in the cream seems to cut or reduce 
the viscosity of the cream, although it causes it to become thicker 
in its consistency. Cream in an advanced stage of ripening is 
brittle, so to speak; that is, if a sample of the properly soured 
cream is poured from a dipper it will not string but break off in 
lumps. 

If very thin cream is overripened, the curd is coagulated. 
When this thickly coagulated cream is churned, the soHd curd 
breaks up into small curdy lumps. These small lumps of curd 
are likely to incorporate themselves in the body of the butter 
and injure its quality, and also its keeping quality. If thin 
cream has been overripened, it should be strained well, and 
care should be taken not to churn it to such a degree as to 
unite the granules into lumps before the churn is stopped. If 
the churn is stopped while the butter is in a granular form, the 
most of these curdy specks can be separated from the butter 
by copious washing. Some specks are likely to remain in the 



CONDITIONS AFFECTING THE CHURNABILITY OF CREAM 249 

butter when the cream is in such a condition, but by following 
the plan outlined enough of the specks can be removed from the 
butter so that its commercial quality will not be injured. The 
degree of ripeness of cream does not have any effect upon the 
composition of the butter, except in increasing the curd content as 
mentioned. 

Nature of Agitation. — The nature and degree of agitation of 
cream affect the churnability considerably. Many different 
kinds of churns are on the market at the present time. The 
rotary drum-churns, now used almost universally in this country, 
are claimed to give the greatest degree of agitation; that is, 
providing the churn revolves at a proper rate of speed. If 
the speed is so great as to cause the cream to be influenced by 
the centrifugal force generated, rotating it with the churn, then 
no agitation will take place. Consequently the churning 
process will be delayed, if not entirely prevented. If the 
speed of the churn is too slow, the degree of agitation of the 
cream will not be at its maximum, as the cream will tend to 
remain at the lowest portion of the churn without being agitated. 

In the old-fashioned dash-churn the cream was not exposed 
to much agitation. In Europe the upright barrel-churn with 
rotary stirrers inside is mostly used. It is slower than American 
churns, but gives good satisfaction. 

Extensive investigational work conducted by the American 
Association of Creamery Butter Manufacturers, under the 
direction of one of the authors, has shown that there are 
several factors which have a direct bearing upon the exhaustive- 
ness of the churning of cream. With very sour cream that 
has been pasteurized, the loss of fat in buttermilk is much 
larger than is generally recognized by buttermakers. The 
average loss of fat in buttermilk, according to hundreds of 
analyses made by the American Association of Creamery 
Butter Manufacturers, is more than five-tenths of one per cent. 

The loss of fat in buttermilk varies somewhat with the 
seasons of the year. During the hot weather in the summer 
months, especially in the flush, the loss of fat in buttermilk 
is greater than in the fall and winter months. One creamery 



250 CHURNING AND WASHING BUTTER 

that makes a practice of testing its buttermilk daily reported 
to us that for the months of June and July their average loss was 
.85 per cent, some samples running as high as 1.25 per cent. 
Their tests were made by the Mojonnier method. So there 
is no question concerning the accuracy of the results obtained. 

The high per cent of fat found in buttermilk during the 
period when cream is very sour is no doubt caused by the 
high acid coagulating a portion of the casein into small hard 
lumps, which are not entirely broken up by the process of 
neutralization or churning. 

Another thing that wall affect the loss at this period is, 
the amount of cream received is very large; buttermakers are 
crowded with work, churns are filled too full, and cream is not 
held for a long enough period at churning temperature to 
thoroughly chill the fat. The result is that the large globules 
unite quickly in the process of churning, due to the soft condi- 
tion of the fat, and the smaller fat globules are carried off in 
the meshes of the casein into the buttermilk. It may be 
possible that the high acid in the cream partly removes the 
film from the larger fat globules, and in the process of churning 
they break up into smaller particles of fat. We have no 
positive knowledge that this is the case. 

In the investigation pursued by the American Association 
of Creamery Butter Manufacturers it was found that where 
the churn is filled about one-third full and the cream is held 
for several hours, or overnight, at churning temperature a 
more exhaustive churning is obtained than where cream is placed 
in the churn immediately after being cooled. Where the lack 
of churn or vat space compels quick churning of the cream, 
it is better to cool the cream down four or five degrees below 
the normal churning temperature. The temperature that 
cream can be churned at will depend upon the per cent of fat 
in the cream. Cream that contains from thirty to thirty-five 
per cent fat can be churned at a very low temperature, especially 
cream that contains a high per cent of acid. 

The speed of the churn has also a direct bearing on the 
temperature at which cream can be churned, and also a bearing 



CONDITIONS AFFECTING THE CHURN ABILITY OF CREAM 251 



on the loss of fat in the buttermilk. The speed of the churn 
will depend, to some extent, upon the diameter of the churn 
and the kind of churn used. We find the following speeds give 
very satisfactory results : 

Simplex churn, 24 revolutions per minute. 

Disbrow, Victor, Dual and Perfection churns, from 32 to 
35 revolutions per minute. 

Where a churn is run at a low speed, the temperature of 
the cream will have to be higher to cause the fat globules to 
unite, due to the lack of sufficient agitation. 

From microscopical examination made of buttermilk, where 
the loss was high, it was found that the fat seemed to be lodged 
in the meshes of the casein. When placing buttermilk in bottles 
in the laboratory and permitting it to stand overnight, and 
taking samples from the upper or watery portion, the test of 
fat in this liquid portion was very low, while in the lower por- 
tion, which contained the casein, the per cent of fat was 
exceedingly high. 

The following tests of the upper and lower portions of twelve 
samples of buttermilk from different churnings were made after 
allowing the samples to stand in half pint bottles overnight. 
About half the liquid, or the upper portion of the buttermilk, 
was decanted from the bottle in each instance, and a comparison 
of its test was made with that of the lower portion. 



Number 


Test of upper 


Test of 


of sample 


liquid portion 


lower portion 


I 


.48 


1.07 


2 




20 




SO 


3 




20 




SO 


4 




18 




56 


5 




38 




60 


6 




02 


I 


06 


7 




30 




39 


8 




14 




38 


9 




18 




44 


10 




14 




S7 


II 




iS 




74 


12 




II 




S8 



252 CHURNING AND WASHING BUTTER 

Cream that is separated from sweet milk at the creamery 
can be ripened or soured to a fairly high degree of acidity 
without having the lumpy condition referred to above, and 
a very exhaustive churning can be had from the same, 
whether pasteurized or unpasteurized. Where various lots 
of sour cream are received at the creamery, the average per 
cent of acidity of the entire lot when mixed together may 
not be very high, but some portions of this cream possibly have 
contained an acidity of well over i per cent; hence, the 
loss of fat in such cream would be greater than if the cream 
had been separated from sweet milk and where the souring 
was under the control of the maker. To get an exhaustive 
churning with sour cream, the same should have the acidity 
reduced to a low degree. Partial neutralization has the 
effect of putting the casein in a more flocculent condition; 
hence, the loss is not as great. 

Neutralization should always be done before pasteuriza- 
tion, as otherwise the heat of pasteurization will precipi- 
tate some of the casein into hard lumps, which will not 
be broken by the agitation of the churn in the process of 
churning. 

As far as the working of butter goes, any of the modern 
churns will do efhcient work, especially when the maker has 
got himself accustomed to the churn he is operating. 

Size of Fat-globules. — Cream containing large fat-globules 
churns more quickly than cream containing small globules and a 
more exhaustive churning can also be obtained from it. It is, 
however, impossible to obtain cream which does not contain any 
of the small globules. The minute globules are always difficult 
to remove from the serum, whether it be in the churning or in 
the separation. In the churning there is a certain force which 
always tends to hold the globules in place. This force acts in a 
correspondingly greater degree upon the small globules. They 
are held in position and move only when the cream is exposed to 
agitation. Cream containing larger globules allows them to 
escape from their position with greater ease than does cream 
containing the minute globules. The globules which are not 



COLOR 253 

removed from the buttermilk during the churning process are 
largely of the small type. 

Straining of Cream. — Before the cream is transferred from 
the ripening-vat to the churn it should be strained through a 
fine perforated tin strainer. This can be conveniently done 
during the changing of the cream from the ripening-vat to the 
churn. Special strainers are now manufactUT-ed which can 
be hooked onto the churn, and the cream can run directly from 
the ripening- vat through the strainer into the churn. This 
straining of the cream separates all the lumps which r.re likely 
to appear. It also separates any other coarse impurities which 
may be present. If these impurities were not separated they 
would probably be embodied in the butter and cause an unsightly 




Fig. 95. — Cream and milk strainer. 

appearance. They would also be likely to injure the keeping 
quality of the butter, but this would depend, of course, upon 
the character of the impurities. 

Color. — In order to maintain a uniform color in the butter 
during the different seasons, it is essential that some artificial 
color be added at ce*-tain times. During the latter part of 
May and the early part of June the butter has a rich yellow 
color, which is accepted as the standard color of butter. This 
is often referred to as the " June color." 

There are several different butter-colors on the market, for 
which special merits are claimed. All the colors, so far as known, 
are efficient in imparting color to the butter without materially 
coloring the buttermilk. A good butter-color should be a sub- 
stance which does not impart a bad smell or taste to the butter. 
It should possess strong coloring properties, so that very little 



254 CHURNING AND WASHING BUTTER 

of it would have to be added in order to impart the desirable 
color. It should not be injurious to health. Some colors are 
prepared from the fruit of the annato tree, which grows in the 
East Indies and South America. The coloring matter on the 
inner part of the covering of this fruit is dissolved in a suitable 
oil, such as sesame or hemp. 

Before any of the proper commercial butter-colors were put 
upon the market, extracts of carrots, marigold, saffron, and 
annato were used. The yolk of eggs has also been used to 
some extent. It is said that carrot-juice is the most healthful 
butter-color. 

The amount of color to add depends upon the market require- 
ments, and upon the season of the year. As was mentioned 
before, in June little or no color should be added. As the summer 
season advances the amount of color added can be gradually 
increased. During winter, while the cows are on dry feed, 
the maximum amount of color is generally used. Color require- 
ments of the butter vary considerably at the same season of the 
year. American markets demand a higher color than European 
markets. The northern markets desire a Kght straw color, 
while the southern markets want a deeper color, almost an 
orange color. The Jewish trade requires uncolored butter. 
In some of the European countries no color is used. The 
EngHsh market, which is the greatest butter market in the world, 
demands butter that has a very light straw color. The main 
object in coloring butter is to maintain a uniform color during 
the different seasons of the year. The amount of color to add 
during the different seasons will usually vary between none and a 
trifle over 2 ounces for every 100 pounds of fat. 

The color should be added to the cream before the churn 
has been started. If this has not been done, the butter can be 
colored by mixing the color with the salt. The salt should 
then be well distributed and worked into the butter until the 
body of the butter assumes a uniform color. The chief objec- 
tion to this method is, that it is difficult to work in the color 
thoroughly without injuring the butter. 

The sole object in adding color is to give the butter a more 



WHEN TO STOP THE CHURNING 255 

attractive appearance. It neither adds to nor takes from the 
flavor or food value of butter. Hence the shade of color should 
be such as will make the butter most attractive in appearance. 
This varies somewhat with the market to which the butter is 
going. 

When to Stop the Churning, — Different makers have various 
ways of ascertaining when the churning process has been com- 
pleted. Some determine the proper churning stage by the size 
of granules, others by the height at which the butter floats in 
the buttermilk. Others again depend upon the appearance of 
the buttermilk. It is well to let all of these factors influence 
the operator in deciding when the churn should be stopped, as no 
one of them may be a sufficient indication. 

The size of the granules is the most common factor that 
determines the time when the churn should be stopped. It 
has been a general rule in the past to stop the churning when 
the granules are a little larger than wheat-kernels. As a rule 
it is safer to carry the churning on a little further until the 
granules increase to the size of corn-kernels, irregular and flaky 
in shape. At this stage the buttermilk will usually appear 
bluish in color, and the butter is raised above the buttermilk 
a considerable distance. When the butter is churned to too 
small granules, many of them will go through the strainer into 
the buttermilk, and cause a considerable loss. When butter 
in such shape is washed in medium-cold wash-water, the granules 
continue to remain in a separate state. When salt is added, 
the moisture is extracted from them, and the water is likely to be 
caught in holes and crevices during the working and cause leaky 
butter. If the churning is carried on a little further, the granules 
will not escape into the buttermilk, the churning will be more 
complete, and the moisture will be incorporated in a better con- 
dition. 

Overchurning should be avoided as much as underchurning. 
If butter is overchurned in the buttermilk, it will retain a large 
amount of the buttermilk, which will be very difficult to remove 
by washing. Overchurning butter, especially at a medium- 
high temperature, is very effective in increasing the moisture- 



256 



CHURNING AND WASHING BUTTER 



content of butter, and should be guarded against for that reason. 
Butter containing more than i6 per cent water is not permissible 
on the American market. 

When cream is in a poor condition it should not be over- 
churned, as the incorporation of buttermilk produces a very 
rank and unclean flavor in the butter. Cream in such condi- 
tion also contains many undesirable germs, which, when incor- 




FiG. 96. — Butter from i pound of fat in cylinders, showing the effect of differ- 
ent percentages of water upon quantity. The water-content of these samples 
ranges between 8 per cent and 19 per cent, 

porated into the butter, will cause it to deteriorate to a great 
extent. When the cream is in poor condition, the churn should 
be stopped as early as is consistent with the completeness of 
churning. The buttermilk should be removed and the butter 
washed thoroughly in clean, pure wash-water. If the wash- 
water is added while the butter is in this granular condition, the 
buttermilk can be very effectively removed. If one washing is 
not sufficient, wash three or four times. In such a case the tem- 



CONDITION OF WATER IN BUTTER 



257 




Fig. 97. — Butter sample, 
15.61 per cent water. 



Fig. 98. — Butter sample, 
15.31 per cent water. 




Fig. 99. — Butter sample, 13.37 per cent water; leaky, 2 per cent brine. 

Microscopical views showing condition of water in butter. Fig. 97 shows that 
the water has been incorporated in the form of very minute particles. Storch 
found from nine million to sixteen million water particles per cubic millimeter. 
Such butter appears dry and a little dull. Fig. 98 shows the water incor- 
porated in medium-small particles. There were on an average three and three- 
fifths millions of water particles per cubic millimeter in such butter. Fig. 99 
shows condition of water in leaky butter. Storch found about two and one- 
half million water particles per cubic millimeter in butter having such a body. 
(Views by Storch.) 



258 CHURNING AND WASHING BUTTER 

perature should be low. If the temperature of the wash-water 
is high, and the butter is washed excessively, it will contain too 
much moisture when it is finished, and is likely to be salvy. 
If washed with water at a low temperature the butter will not 
incorporate so much water. What it does incorporate in excess, 
will, as a rule, be expressed during the w^orking of the butter — a 
result due to its firmness. 

If the attempt is made to incorporate water by working the 
butter in water after the salt has been added, while the butter is 
in a hard, granular condition, it will usually appear leaky. 

If cream is in a good condition, overchurning to a small extent 
does not produce any bad results. The germs which are present 
in pure and well-ripened cream are not deleterious to the keeping 
quality of the butter. The amount of butter-m_ilk incorporated 
in the butter is not sufficient to cause any bad effects upon its 
quality. If the cream is in proper condition it is difficult to 
incorporate any more than 3 per cent of curd into the butter. 
While overchurning is not to be recommended, if it is at any time 
desirable, it should be done in the washwater rather than in the 
buttermilk. 

Churning Mixed, Sweet, and Sour Cream. — When two lots of 
cream are to be churned, one sweet and the other sour, they 
should be churned separately. If the two lots of cream are 
mixed together, the sour cream churns more quickly than the 
sweet cream. As a consequence the churn is likely to be 
stopped before the fat from the sweet cream has been completely 
separated from the serum. 

At some of the creameries conditions are such that the oper- 
ator may be tempted to mix the two lots of cream. Where 
sweet cream arrives at the creamery just previous to churning 
time, it is advisable not to mix the sweet cream with the sour. 
It is, as a rule, better to carry the sweet cream over to the next 
churning, or, if necessary, churn it separately. 

Difficult Churning. — Difficult churnings in creameries are 
not very common. In farm butter-making they are more fre- 
quent, especially in the fall. At this time the cows are usually 
well advanced in the period of lactation, and early in the winter 



DIFFICULT CHURNING 259 

they are often fed on food which causes hard butter fat, as 
described under "Effect of Food upon Fat." In the fall or 
early winter, a large portion of the milk is usually obtained 
from strippers, or cows almost dried up. Such milk contains a 
large portion of the small fat-globules. Difficult churning 
resulting from such conditions can usually be remedied by ripen- 
ing to a higher degree of acidity and churning the cream at a 
higher temperature. 

Complaints are occasionally heard of difficult churning which 
cannot be remedied by such treatment. Sometimes cream froths, 
and will not agitate in the churn. Such a frothy condition has 
in some cases been found to occur even though the cream may 
seem to be in an ideal condition for churning. It is believed 
by some, notably Hertz, that such a condition in the cream is 
brought about by a disease of the cow. Weigman has studied 
and isolated a ferment which caused a soapy condition of milk 
and cream. It is possible that such exceedingly difficult cases 
in churning m.ay be due to a disease of the cow, and it may also 
be due to certain ferments that produce a soapy condition of the 
cream. 

If thick cream at a very low temperature is put into the 
churn, it som.etimes causes difficult churning. When such 
cream is first agitated in the churn it incorporates considerable 
air. This air, together with the various gases developed at a 
low temperature, does not readily escape. The viscosity of it is 
so great that it will not release the air present. As a conse- 
quence it assum.es a stiff consistency, much the same as the beaten 
white of an egg. If cream froths in the churn as mentioned, 
a Httle warm water thrown on the outside of the churn will 
often start the agitation of the cream within. If a combined 
churn is used the rollers may be put in gear, and the churn 
revolved in slow gear. This will often start the cream to agitate. 
If these two remedies are not sufficient, a little water, lukewarm if 
necessary, may be added directly to the cream. By letting 
the churn stand a short time, the cream will usually condense 
into a liquid form again, and many times the churning process 
can then be completed. This latter method, however, usually 



260 CHURNING AND WASHING BUTTER 

requires more time than can be profitably spared. If the churn- 
ing difficulty is of a serious nature the remedies are: 

(i) If produced by a certain cow, or herd, find out whether 
it is produced by a fermentative process, or by other abnormal 
conditions of the cow. 

(2) Change the food of the cow. A succulent food will 
usually cause the cow to secrete more milk, and of a different 
nature. 

(3) If produced by a ferment, endeavor to control the fer- 
mentation as previously described. 

(4) Ripen the cream to a higher degree of acidity, 

(5) Skim thicker cream and churn at a higher temperature. 
The last three methods will cure most cases of difficult 

churnings. 

Keeping Churn Sweet. — It has been mentioned before that 
butter absorbs foreign odors very readily. If the churn is not 
kept in a pure, sweet condition, the butter will be exposed to the 
undesirable odors and its commercial quality will be impaired. 
The best butter cannot be produced in a foul-smelling churn. 
As churns often are not used every day, they very readily assume 
this impure condition, and it is essential that special care be 
taken in keeping them clean. 

The best method of keeping churns in good condition is to 
rinse the churn in two waters at the end of each churning. 
The first rinsing should be made with lukewarm water, the 
second with scalding hot water. Some prefer to turn the 
churn over with mouth down. Others prefer to allow the cover- 
hole to turn up. When the churn is turned with the cover- 
hole down, the remaining steam on the inside of the churn will 
not escape. It will condense inside of the churn, and cause the 
churn to remain in a damp condition overnight or even longer. 
If the churn is turned with the cover-hole up the dust and other 
impurities, if present, are likely to settle into the churn. A good 
way is to turn the churn over so that the cover-hole points to 
one side. The churn should be thoroughly drained first, other- 
wise some water will remain in the bottom. When the churn 
is left with the cover-hole at one side, the steam can escape, 



KEEPING CHURN SWEET 261 

and the heat absorbed from the wash-water will dry the churn 
thoroughly. Many makers rinse the churn only once and use 
scalding hot water. This method is likely to scald the remaining 
curd on to the wood; secondly, one rinsing is not enough to 
insure a clean churn. The first rinsing with lukewarm water 
removes the major portion of the buttermilk and brine, and to a 
certain extent warms the wood of the churn, so that when the 
second rinsing with scalding hot water is completed, the churn 
has been thoroughly scalded. In addition, the churn is clean, 
and no food is left on which germs can thrive. The churn is 
also left warm, and in that condition will dry quickly. 

Some makers prefer to keep the churn in a good condition by 
sprinkling salt on the inside after washing. This is not to be 
recommended, as all churns contain more or less iron-ware on 
the inside. Salt, while a fair germicide, causes the formation 
of rust on all iron with which it comes in contact. After a time 
this rust will scale off to a certain extent and become incorporated 
with the butter. 

If the churn is treated daily in the manner described above 
and then at the end of the week treated with slaked lime, 
it can be kept in a good sweet condition. The lime should 
be freshly slaked and in a liquid condition when put in the churn. 
A pailful or two of this fluid will be sufficient for each churn. 
By rotating the churn a few times the lime will be spread all 
over the inside of it. Let the churn remain in this con- 
dition until ready for use again. When ready for use, put in 
'some warm water, and the lime will readily come off. But if 
it has been allowed to remain in the churn too long, it will form a 
lime carbonate, and will be more difficult to remove. 

Lime is one of the best disinfectants and deodorizers that can 
be used in a creamery. Some of the best butter-makers use it 
every day on all the wooden utensils, such as butter-workers, 
churns, etc. Lime can be used more advantageously in Amer- 
ican creameries than it is to-day. Many creameries would be in 
a much sweeter and purer condition if they were given a good 
coat of whitewash on the inside once a month. Refrigerators, 
wooden utensils, and rooms of any kind can be kept in a good, 



262 CHURNING AND WASHING BUTTER 

sweet and pure condition by whitewashing or sprinkling a little 
lime on them. 

In the preparation of a new churn for use it is a good plan 
to treat it with milk of lime in the manner already described. 
It will fill the pores of the wood and harden it, and remove all 
danger of imparting a woody flavor to the butter of the first 
churnings made in the churn. 

To Prevent Butter from " Sticking " to the Chum. — At times 
churns get into a condition in which butter sticks or adheres to 
them more or less. Sometimes it requires treatment with a weak 
acid solution to overcome this difficulty, and sometimes treatment 
with an alkali solution is needed. If treatment with acid is 
what is needed, a weak solution of either sulphuric or muriatic 
acid may be used — say a pint to loo gallons of water. The 
acid must be added carefully to the water in the churn and 
none of it must be poured directly upon the wood. The churn 
is revolved with this solution in it, for about five minutes at a 
time, at intervals extending over a period of several hours. 
It is then rinsed with warm water and then with water containing 
a little of some good washing powder, such as Wyandotte. 
If treatment with an alkali solution is needed, which is the case 
if fat has soaked into the wood, a suitable washing powder may be 
used to remove the difficulty. The following is an extract from 
a letter received from one of our leading creameries which had 
written for and received suggestions from one of the authors for 
overcoming this difficulty: " We received your letter in regard to 
the trouble we had with the butter sticking to our churn. We 
are pleased to advise that we have apparently eliminated all 
of this condition. When we received your letter suggesting 
remedies which might stop this condition, we at first used the 
muriatic acid but without any results whatever. Then our 
butter-maker took about three pails of Wyandotte, put in a small 
amount of water and heated with steam until he made a sort of a 
paste out of it. He then put it in the churn and gave it several 
revolutions and let it stand overnight, then washed it out 
thoroughly with hot water. The first time it seemed to help 
it very considerably, so we gave it another dose a day or two 



WASHING OF BUTTER 263 

later and it has relieved the whole condition. He is of the 
opinion that if this is used when the butter shows any ten- 
dency to stick to the churn, it will keep the churn in good con- 
dition right along." 

WASHING OF BUTTER 

Purpose of Washing. The chief object of washing butter 
is to remove as much buttermilk as possible. The more impure 
the cream is, the greater is the importance of getting the butter 
thoroughly washed. In the winter, when it is cold, and the 
cream is in good condition, some makers do not wash the butter 
at all. But this is not a safe method. The removal of the 
buttermilk constituents should be as complete as conditions will 
permit. 

Temperature of Wash-water. — The temperature of wash- 
water should be as nearly like that of the cream when churned 
as is consistent with the other conditions. It is quite a regular 
practice in many creameries, particularly in summer, to temi.per 
the wash- water to about 2° below the churning temperature of 
the cream. Extreme and rapid changes in temperature should 
always be avoided. Occasionally it is necessary to use water 
that is colder than the cream; at other times it is necessary to 
use wash-water at a higher tem.perature than that of the cream. 
If the butter churns soft, do not use ice-cold wash-water to chill 
the butter, as it has a tendency to give butter a tallowy appear- 
ance. Neither should hard butter be quickly softened by using 
wash-water at a very high temperature, as it is Hkely to cause the 
butter to assume a greasy and slushy texture. If it is necessary 
to change the degree of hardness of the butter, change it grad- 
ually by using water at a moderate temperature and allowing the 
butter to be in contact with it a longer time without agitating 
it much. 

The regulation of the condition or degree of firmness of butter, 
for the proper working of it, should never have to be accom- 
plished to any great extent by means of the wash-water. This 
is not the real purpose of washing butter. If the churning tern- 



264 CHURNING AND WASHING BUTTER ; 

perature of the cream be right, the butter will be in proper con- 
dition for washing and working. If the churning temperature 
be not right it is difficult through any device that may be 
adopted subsequently — such as tempering the wash-water — to 
bring the butter into the best condition for salting and working. 
Regulation by means of a change in temperature of the wash- 
water will prove a partial, but not a complete remedy — par- 
ticularly if the butter be very soft when it comes. 

Unless the butter is of very poor quality, excessive washing 
should be avoided. Cold water is said to absorb a considerable 
portion of the flavoring substances. If the quality of the butter 
is poor, many of the undesirable flavors and odors are removed 
by excessive washing; while if the butter has a fine, rich flavor, 
it should be retained, and not extracted by washing the butter 
more than is needed. No definite temperature can be given, as 
the temperature of wash-water must vary according to the hard- 
ness of the butter when churned. 

If the temperature of the wash- water is too high, and the 
churning in the wash- water is continued a very long time, much 
water will be incorporated in the butter. If the butter is quite 
firm in the first place, and the temperature of the wash- water 
is not above 60° F., there is not much danger of getting too 
much water in the butter. Rapid changes in the degree of 
hardness of the butter in the presence of water are conducive to a 
high moisture-content. Very soft butter chilled in very cold 
water, and hard butter softened in very warm wash-water are 
two conditions which should be avoided. 

As to the quantity of wash water that should be used : with 
cream of average richness, it will be about the same as that of the 
buttermilk; with very rich cream a Kttle greater. In washing 
the butter the churn is usually run from 10 to 15 revolutions on 
high speed. Some, instead of following this practice of churning 
the butter in the wash water, run the churn about 2 to 5 revolu- 
tions at slow speed with the worker in gear; modifications and 
combinations of these two methods are made. For instance, 
where butter is first washed or sprayed and a second wash-water 
is used, some adopt the practice, during the second washing, of 



WASHING OF BUTTER 265 

revolving the churn a few times on high speed while others put 
the rolls in motion using the slow gear. 

Butter from cream of good quality, churned at the right 
temperature, needs less washing than butter from cream of poor 
quality or butter churned at too high a temperature. Two 
washings should suffice when the cream is of good quality, and 
with such cream some wash the butter only once if the wash- 
water runs off clear. In order to possess good keeping qualities, 
butter must have the buttermilk well washed out of it. Butter 
from cream of poor flavor requires more washing than butter 
from cream that is clean in flavor. 

Kind of Wash-water to Use. — In the washing of butter, it is 
very essential that water used should be the best obtainable. 
The creamery water-supply is evidently much better now than 
it was years ago. Pond- wells and shallow wells are gradually 
passing out of existence, but there are yet many shallow wells 
from which water is drawn for creamery purposes. Water from 
wells may appear to be pure, and yet contain germs which are 
deleterious to dairy products, and especially to the keeping qual- 
ity of butter. That water of average purity contains such germs 
has been demonstrated in this country, as well as in foreign 
countries. Shallow well water contains on an average about 
15,000 germs per cubic centimeter, but Miquel has found that a 
rapid power of multiplication characterizes the bacteria in pure 
spring-water, while in impure water the multiplication is slower. 
Water containing only this number of germs is, as a rule consid- 
ered very pure. Most creameries, however, pump their water 
into a tank overhead in the cream.ery, where it is contaminated 
with bacteria and impurities of different kinds. 

Shallow wells are usually surrounded with conditions which 
do not guarantee a creamery pure water during the different 
seasons of the year. In the spring, when rains are frequent and 
heavy, unwholesome surface-water is likely to seep in through 
the sides. Such wells may also serve as traps for small animals. 
The presence of an animal in the well is sure to cause undesirable 
odors and a multitude of undesirable and putrefactive organisms. 

Water from deeply drilled wells, even if it is pure in so far 



266 CHURNING AND WASHING BUTTER 

as its germ-content is concerned, is in many cases turbid and 
sandy, and needs to go through a process of purification as much 
as does the shallow well water. 

METHODS OF PURIFYING WASH-WATER 

There are two practical and effective methods of purifying 
wash-water, viz., (i) Filtration, and (2) Pasteurization. Which 
of these two methods is the most practicable and the most 
effective in the creamery depends upon the conditions and upon 
the quality of the water. In the case of water from deep wells, 
which contains little or no organic matter, but at the same time 
is infested with undesirable germs, pasteurization is perhaps 
more expedient. Filtration, if the same degree of thoroughness 
is to be reached as in pasteurization, is a comparatively slow 
process. Pasteurization of wash- water is a trifle more expensive 
than filtration. Wash-water can be pasteurized at the same 
time that the churning is being done, thus economizing in time 
and fuel. Pasteurization is quite effective in rendering the water 
germ-free, but it is not so effective in removing any organic 
matter or other tangible impurities which may be present. If 
the creamery does not already have a pasteurizer, filtration can 
be employed very profitably, and under average conditions it 
will perhaps give the best results. 

Filtration. — Filtration is inexpensive, and is a very efficient 
method of purifying wash- water. It seems strange that bac- 
teria can be removed from water by passing through layers of 
sand, gravel, coke, and charcoal, but such is the case. Filtra- 
tion is applicable to all kinds of water; even if the water appears 
pure, it is well to filter it. Fewer germs and fewer varieties 
of micro-organisms are apparently found in deep well water 
than is the case in water from surface-wells; hence the ferments 
which are present will have a free field for developing in the 
absence of competing forms. If a sample of water which is 
rich in micro-organisms is violently shaken with a certain 
amount of charcoal, coke, chalk or similar substances, and then 
left for a time to settle, the pure layer of water at the top will be 



METHODS OF PURIFYING WASH-WATER 267 

almost entirely free from germs, and in some cases entirely 
sterile. It used to be thought by older German investigators 
that these different filtering substances had almost miraculous 
power of removing organisms from water. 

The factors which are to be considered in successful filtration 
are: 

(i) Storage capacity for unfiltered water. 

(2) Construction of filter-beds. 

(3) Rate of filtration. 

(4) Renewal of filter-beds. 

(i) Concerning the storage capacity, nearly all creameries 
have storage- tanks overhead in the creamery; so far as that is 
concerned, however, filtration can be successfully carried on 
continuously as well as intermittently. 

(2) The construction of the filter-bed used in the experi- 
ment carried on at the Iowa Experiment Station, Ames, Iowa, 
is as shown in Fig. loi. The approximate proportionate depth 
of each layer in the bed is as follows, beginning at the bottom: 

Two inches small flint stones; 22 inches fine sand; 12 inches 
fine coke; 9 inches charcoal; 2 inches fine stone or coarse gravel. 
The layer of fine sand should not be less than 15 inches. It has 
been asserted that a few pieces of old iron mixed in the filter-bed 
are beneficial. Alum, lime, and copperas have been recom- 
mended for clarifying and deodorizing very impure water. As 
these substances are soluble they should not be used in filter- 
beds, which are intended for the filtration of water for potable 
purposes. The filtering-can was made from 22 galvanized iron. 
The height of can is 48 inches; diameter, 18 inches. The bottom 
of the can is slanting towards the faucet, or opening. Thus 
no water is permitted to stand on the bottom and afford oppor- 
tunities for germs to accumulate. On the inside are three plates. 
One lies horizontally, near the bottom, and upon it the filtering- 
material rests. Another Hes on the top of the fine sand. Both 
of these plates were perforated with many small holes. Near the 
top is placed a concave plate with a hole near the center. This 
plate directs all the water to the center of the filter-bed, and thus 
the water gets the full benefit of the filtering process. The 



268 



CHURNING AND WASHING BUTTER 



total cost of this filtering-can when complete was $ii.ii. Since 
the time when this can was constructed prices have advanced 
considerably. 

(3) The rate of filtration is necessarily governed by the depth 
of the filter-bed, the character of the material used, and its 




Coai-sse gravel S&'y<fe°o°i§5^» 






r^ 



d^; 



Gravel ^%°^o°J'o?'3°^^°o'oo 
Coarse gravel /^c^6§ao'c|S2 




Fig. 



Fig. 101. 



Fig. 100. — Filter-can; i, overflow; 2, inlet of tap-water; 3, outlet of filtered water. 

Fig. 1 01. — Cross-section of filter-bed and can: i, overflow; 2, inlet; 3, outlet of 
filtered water; 4, perforated galvanized-iron plate; 5, perforated galvanized- 
iron plate; 6, concave galvanized-iron plate with hole in center. 



fineness. The water passes through the charcoal, coke, and 
gravel quite rapidly, yet the substances are very strong barriers 
to the passage of micro-organisms. The sand layer does not 
admit of such rapid filtration. Fine sand, however, is one of the 
best filtering substances that can be had. The rate of filtra- 
tion can be regulated by increasing or decreasing the depth of the 



METHODS OF PURIFYING WASH-WATER 269 

fine-sand layer. In a general way, the slower the rate of fil- 
tration is, the more thorough it is; and, vice versa, the more rapid 
the rate of filtration, the more incomplete is the removal of 
the bacteria. If the filter-bed is constructed as described 
above, the rate of filtration will be about i8 gallons per hour, 
and about 96 per cent of all the germs present will be removed, 
together with the impurities present in suspension. 

(4) The filter used at the Iowa Experiment Station was in 
constant use for about three months, without having been 
changed. At the end of this time it did as efficient work as 
at any previous time. The length of time a filter-bed can be 
used without being changed depends upon the purity of the 
water to be filtered, and also upon which kind of filtration is 
used, the continuous or the intermittent. The more impure 
the water which has to be filtered, the oftener the filter-bed 
should be changed. Whenever the rate of filtration is decreased 
to such an extent as to make the process impracticable, the 
filter-bed should be taken out and cleaned. If the water to be 
filtered is of average purity, a change of the filtering-material 
once every four months is ordinarily sufficient, no matter whether 
continuous or intermittent filtration is used. A filter-bed may 
do efficient work even a longer time than this. The same filter- 
ing-material can be used again providing it is thoroughly washed 
previous to replacing it in the filtering-can. 

Kinds of Filtration. — The two kinds of filtration in use are 
(i) Continuous, and (2) Intermittent. 

By the continuous method of filtration the inflow of water 
into the can is constant during night and day. The stream of 
water admitted into the filter-can is sufficient to cause the 
surface of the filter-bed to be covered with water all the time. 
This method excludes all oxygen from the filter-bed, except 
that which is in solution in the water. 

During the process of filtration a slimy coat is deposited on 
the fine sand. This seems to be the real agent absolutely 
necessary in order to eliminate bacteria by a process of filtration. 
A filter-bed without this slimy deposit on it simply takes out the 
coarse organic and inorganic matter held in suspension, without 



270 



CHURNING AND WASHING BUTTER 



removing the bacteria. If some bacteria are removed with 
the matter held in suspension, others are carried along from the 
filter-bed. Owing to this, a new filter-bed must be kept in 
operation a few days before the filtered water can be considered 
pure and ready for use. The following table illustrates how the 
germ-content of water is decreased as the process of filtration is 
carried on during the first few days: 









Filtered 


Unfiltered 








Water, 


Tap- water, 








Germs per 


Germs per 








c.c. 


c.c. 


No. 


I. 


Taken when filter-bed was first used 


20,000 


107 


No. 


2. 


Taken when filter-bed had worked i day. . . . 


860 


118 


No. 


.3- 


Taken when filter-bed had worked 3 days . . . 


370 


96 


No. 


4- 


Taken when filter-bed had worked 5 days . . . 


48 


54 


No. 


.=;• 


Taken when filter-bed had worked 7 days . . . 


3 


73 


No. 


6. 


Taken when filter-bed had worked 9 days . . . 


5 


89 



It will be seen from the table that during the first three days 
the filter-bed was in use the filtered water contained more 
germs than the unfiltered. Good results were not obtained 
until the seventh day. In order to be on the safe side it is 
best to expose the filter-bed to continuous filtration for about 
nine days before the water is used. 

The slimy coat referred to above is formed by certain germs. 
These germs then constitute the real agent of filtration. In 
order that these micro-organisms may do efficient work oxygen 
is essential. Well-water of average purity contains enough 
oxygen in solution without employing an intermittent process of 
filtration, and consequently for creamery purposes the con- 
tinuous method of filtration is to be recommended. 

Intermittent. — The intermittent process of filtration is used 
where comparatively impure water is being purified, such as in 
purifying water for large cities. If the continuous process 
of filtration were employed in such instances, the filtered water 
would not be free from germs, due to the fact that impure river- 



METHODS OF PURIFYING WASH-WATER 271 

water does not carry enough oxygen in solution to supply the 
germs which form the real filtering agency. 

If the intermittent process is used, the first water filtered after 
the intervening period should not be used. During the inter- 
mission, or during the time that the water is shut off, germs 
develop and come through the filter-bed with the water that is 
filtered. 

Advantages of Purifying Wash-water for Butter. — The chief 
advantage of purifying wash-water for butter is that the keeping 
quality of the butter is improved, and if the proper skill and 
care have been appKed in the other steps of manufacture, a pure 
sanitary product is obtained. The sanitary efficiency reached 
by purifying the wash-water constitutes no small consideration. 
Germs producing contagious diseases are thus prevented from 
spreading. 



CHAPTER XVIII 
SALTING AND WORKING OF BUTTER 

Objects of Salting, — (i) The chief object in salting butter 
is to impart a desirable salty flavor. (2) Within limits, salt 
improves the keeping quality of butter. (3) Salt facilitates the 
removal of buttermilk. 

Amount of Salt to Use to Produce Proper Flavor. — The proper 
amount of salt to use in order to impart a desirable flavor depends 
chiefly upon the market. Some consumers prefer a medium 
high salt-content in butter; others, again, like butter which 
contains very little salt. The English market demands rather 
light-salted butter. In fact, this is the case with prac- 
tically all European markets. American markets, as a rule, 
demand a comparatively large amount of salt, as much as will 
properly dissolve in the butter. Parisian markets and some 
markets in southern Germany require no salt at all. The salt- 
content of butter may vary between nothing and 4 per cent. 
Butter containing as much as 4 per cent salt is, as a rule, too 
highly salted, and part of the salt is usually present in an undis- 
solved condition. Those who like good butter prefer the salt 
thoroughly dissolved and well distributed. 

The amount of salt to be added should be based upon the 
least variable factor. Some creamerjrmen measure the amount 
of salt according to the amount of cream in the churn. While 
the box-churn and Mason butter-worker were being used, many 
makers preferred to weigh the butter as it was transferred from 
the churn to the worker. The method mostly in use now and to 
be recommended is to base the amount of salt upon the number 
of pounds of fat. The amount of salt to use per pound of fat 
varies, therefore, according to the conditions mentioned below, 
and also according to local conditions. Usually from half an 
ounce to one and a half ounces of salt per pound of butter-fat 

272 ■ 



EFFECT OF SALT UPON KEEPING QUALITIES 273 

is most suitable. In whole-milk creameries the salt is often 
estimated per hundredweight or per thousand pounds of milk. 

To get the butter salted uniformly from day to day is very 
important. A variation of i per cent to 2 per cent in the salt- 
content can very easily be detected by the consumer, while 
that much variation in any one of the other chief constituents 
could not be readily noticed. 

The conditions upon which the proper amount of salt depend 
are: First, the amount and condition of moisture in the butter 
at the time the salt is added. If there is a great deal of loose 
moisture in the butter, more salt is necessary. This is due to the 
fact that the salt will go into solution in the water and be 
expressed during working. Secondly, it depends upon the 
amount of working the butter receives, and at what time the 
bulk of working is done, after the salt has been added. If the 
butter is medium firm, moisture in the form of brine is being 
expressed during the working. Consequently, the more butter 
is worked, up to a certain limit, the more brine is being expressed, 
and the more salt should be added to the butter. Thirdly, it 
depends upon the firmness of the butter, the size of the granules, 
and the method of applying the salt. If the granules be inclined 
to be soft and slushy more salt must be added than would other- 
wise be necessary, as more will be carried off during the process of 
working. 

It is undoubtedly due to these facts that the salt-content 
and the condition of salt in butter vary so much at the different 
creameries; they even vary considerably from one churning 
to another at the same creamery. If conditions are uniform in 
the creamery from day to day, the amount of salt to add to 
butter, and the amount of salt retained in the butter when 
finished, will be comparatively uniform. 

It was thought at one time that heavy salting covered defective 
flavors in butter. Such is not the case; it really accentuates 
them. Some of the large creameries make their second-grade 
cream into sweet or unsalted butter. 

Effect of Salt upon Keeping Qualities. — Within certain 
limits salt acts as an antiseptic and improves the keeping qual- 



274 



SALTING AND WORKING OF BUTTER 



ities of butter; but there does not appear to be any advantage 
to be gained from heavy salting. We submit the following short 
tables in support of this view, the first made up from investiga- 
tions by McKay and Larsen at the Iowa Station and the second 
from investigations by Gray of the U. S. Department of Agri- 
culture (Butter scored by McKay) : 







Ounces of 
Salt to 


Scores 












Number 


I Pound 


When 


At End of 


At End of 


At End of 




Butter 


Made 


One Month 


Two Months 


ThreeMonths 




25 


0. 


92.0 


85.0 


75-0 


65.0 


Exp. 13 


26 
27 


0.5 

I.O 


93-5 

92. s 


87.5 
88.0 


85.0 
87.0 


78.0 
80.0 




28 


1-5 


92.0 


90-5 


84.0 


80.0 


E.P. X4 ( 11 


0. 
1.0 


93-0 
94.0 


90.0 
89.0 


80.5 
86.0 


74.0 
87.0 





Per Cent 
of 


Scores 


Num- 


Before 


Stored at 


— 10° F. 


Stored at -|-io°F. 


Stored at -(-32°F. 






Storing 
















Salt 


Five 


Eight 


Five 


Eight 


Five 


Eight 








Months 


Months 


Months 


Months 


Months 


Months 


Some 


individu 


al lots: 
















f 1.02 
I 3.20 


88 


93 


90I 


92I 


90 


90 


86 




89 


90 


88 


89i 


86 


85 


84 




f 1. 10 
I 2.87 


91 


93 


91I 


92 


9ii 


89 


88 




91 


90I 


87 


90 


87 


88 


87 




J 2.00 
I 3-i6 


9i§ 


92i 


89 


89 


89 


91 


88 


3 


89I 


91 


89 


90 


881 


89 


84 




( I-S2 

I 3.28 


91I 


91 


88| 


90I 


88 


88 


82 


4 


89 


89 


85 


87I 


85 


86 


80 


Avera 


ge of all 


Lots in t 


he Exper 


iment 










Light 


















Salt 


1.64 


91.7 


92.6 


90.9 


91.70 


90.6 


90.3 


87.8 


Heavy 


















Salt 


3-44 


91.2 


90.5 


89.9 


90.15 


89.0 


89.0 


85.0 



SALT FACILITATES THE REMOVAL OF BUTTERMILK 275 

Each " experiment " in the first table includes samples of 
butter from the same churning, salted at the different rates 
indicated. 

Each pair or lot of churnings reported in the second table 
were from the same vat of cream. 

The first table shows that salted butter keeps better than 
unsalted butter. The second table shows that light salting is 
just as effective for improving the keeping quality of butter as 
heavy salting. In fact, in nearly all cases lightly salted butter 
came out of storage, at the end of eight months, with a higher 
score than butter that was heavily salted. This would be due 
in part to the salt bringing out defects in flavor. 

Salt Facilitates the Removal of Buttermilk. — That salt 
facilitates the removal of buttermilk can easily be demon- 
strated by observing the escape of buttermilk from the butter 
immediately after the salt has been added and mixed with the 
butter. The first effect of salt when added to the butter is to 
precipitate the curd in the buttermilk. This precipitation is 
greater when a large amount of salt is added than when only 
a small amount is added. The precipitation of the casein in 
the buttermilk sets free the remainder of the buttermilk con- 
stituents; that is, when the casein is precipitated, the whey 
part assumes a more fluid condition and escapes, and the butter 
retains a portion of the curd. Owing to this action of the salt, 
it is essential that the butter should be as completely washed as 
possible, as otherwise it will retain an excessive amount of curd. 
The butter acts in a manner somewhat similar to a filter in 
removing a part of the curd from the other buttermilk con- 
stituents. 

Salt in Relation to Water in Butter. — Experiment has dem- 
onstrated that pure fat is not a salt-dissolving substance. Owing 
to this fact the only salt-dissolving substance in butter is water. 
As water will hold only a certain amount of salt in solution, it 
becomes evident that the amount of salt which can be properly 
incorporated in butter depends upon the amount of moisture 
present. 

The amount of salt which water will hoia in solution at 



276 



SALTING AND WORKING OF BUTTER 



different temperatures varies somewhat according to different 
investigators. According to Gerlach ^ water will dissolve 
35.94 per cent salt at 58° F. This is approximately the tem- 
perature at which salt is worked into butter. Theoretically, 
butter containing 15 per cent of water should be able to properly 
dissolve 5.4 per cent of salt. Butter containing 13 per cent of 
water should be able to properly dissolve 4.68 per cent of salt, 
and butter containing 10 per cent of water should be able to dis- 
solve properly 3.6 per cent of salt, etc. According to experiments 




Fig. 102. — Action of salt solutions of different strength on the proteids of butter- 
milk. (Bui. 263, Gen., N. Y.) 

conducted at the Iowa Experiment Station the maximum per 
cent of pure salt (NaCl) that could be properly dissolved in water 
of butter containing 16.92 per cent of moisture, when worked 18 
revolutions at intervals during two hours, was 16.57 per cent. 
When butter was worked the same number of revolutions at 
intervals, and was allowed to dissolve only one hour, the amount 
of pure salt (NaCl) that was dissolved in the water of the butter 
containing 11.58 per cent moisture was 14.09 per cent. This 
undoubtedly will vary with different brands of salt. 
^ Kemiker-Kalender, p. 219. 



KIND AND CONDITION OF SALT 



277 



It will thus be seen that the property of water to take up 
salt is seemingly lessened when the water is present in a state 
of minute division, as it is in butter. In the first instance 
quoted the butter completely dissolved about 2.7 per cent of pure 
salt; and in the second instance it dissolved only about 2 per 
cent during one hour. 

From the foregoing it is evident that where butter contains a 
high per cent of salt, the salt is not thoroughly dissolved. 

Kind and Condition of Salt. — Salt for butter should be fine 




Fig. 103. — Volumes of the same weight of salt of various brands. 
(Bui. 74, Wis.) 



and readily soluble, so that it will be completely dissolved and 
incorporated when the working of the butter is completed. But 
fineness alone does not determine solubility; some salts that do 
not seem very fine are quite readily soluble, because the crystals 
are somewhat flat and flaky and dissolve quite quickly. Again, 
good dairy salt is clean and white in appearance. When it is 
dissolved in a cylinder of water there should be no settlings and 
nothing left floating on the surface of the water. 

Some salt is chemically impure, one of the impurities being 
magnesium chloride, which, when present to any extent, imparts 
a bitter flavor to butter. Good butter salt is practically free 



278 SALTING AND WORKING OF BUTTER 

of this impurity. According to analysis of the best daiiy salt 
used in Denmark, the composition is as follows i^ 

Per Cent 

Pure salt (sodium chloride (NaCl)) 97-49 

Magnesium chloride (MgClo) 1 8 

Gypsum (calcium sulphate (CaS04)) 05 

Sodium sulphate 21 

Water 2.07 



100.00 



The purest American dairy salt has the following composition: 

Per Cent 

Pure salt 99 . 18 



Magnesium chloride 

Gypsum 

Calcium chloride (CaCb) 

Insoluble matter 

Moisture 



05 
54 
19 
03 
01 



100.00 



Good, moisture-free salt will contain 99 per cent or over of 
sodium chloride (NaCl). Any substance oth^r than this is an 
impurity to the extent to which it occurs. 

Salt readily absorbs odors and moisture. Hence it should 
be kept in a clean dry place. 

Gritty Butter. — " Gritty butter" is a fandliar phrase used 
by expert butter-scorers to indicate that part of the salt is 
present in an undissolved condition. To most consumers this 
condition of the salt in butter is objectionable. When properly 
incorporated, salt should be present in the form of a solution 
in the butter. The gritty condition of the salt in butter may be 
due to (i) poor condition of the salt before it is added to the 
butter; (2) adding so much salt that it cannot be dissolved by 
the water in the butter. The maximum amount of salt that 

1 Boggild, Maolkeribruget, Denmark. 

2 Bui. No. 74, Wis., b} F. W. Woll. 



MOTTLED BUTTER 



279 



butter will dissolve depends upon the amount of moisture present. 
The maximum amount of moisture permissible in butter, accord- 
ing to the Treasury ruling, is i6 per cent. The condition of the 
water in butter prevents the water from being saturated with 
salt during the comparatively short time allowed for salt to 
dissolve during the manufacture of butter. (3) Insufficient 
working. If the butter is not worked enough to distribute 
the salt evenly, some portion of the butter will contain more 
than the other portions. The portion that contains the excess 



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§ 


1 i 


jgfgg^'-'l^ 


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n 


r^^??fl 


■g-m 


A 


■BuLrfAiL^.-... fli 


^KH& 


•0 


'*:#^#: 


:ft# 


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Fig. 104. — Worcester salt. Fig 105. — Diamond crystal salt. 

Types of crystals of buttersalts. 



of salt does not have enough moisture to dissolve the salt; while 
if the salt had been evenly distributed in the butter, all the salt 
would have been properly dissolved. When gritty butter is 
caused by insufficient working, it usually mottles. 

Mottled Butter. — Mottled butter is butter which is uneven 
in color. This may be due to different causes. The most com- 
mon cause, however, is failure to get the salt properly dissolved 
and evenly distributed by the time the working of the butter is 
completed. 



2S() SAI/J'ING AND VV(JRRING OK UUTTKR 

The causes and remedies for mottles are joretty thoroughly 
understood by almost all uj)-to-date butter-makers. Twenty 
or twenty-five years ago mottles constituted one of the leading 
defects found in the creamery butter supplied to our markets. 
Charles Y. Knight, then editor of Chicago Dairy Produce, 
offered a series of prizes for the best methods of preventing 
mottled butter, and many creamerymen entered the competition. 
The result was that a lot of valuable infonnation was obtained, 
which resulted to a very large extent in preventing mottled but- 
ter. Many theories have been advanced as to both the cause and 
the remedy for mottles. 

Long before creameries were established some farmers' 
wives had mastered the art of butter-making to the extent that 
they produced butter of a uniform quality free from mottles. 
This was accomplished by their methods of working. Possibly 
they had no knowledge of what actually caused mottles, but 
they knew that if they worked the butter sufficiently to thor- 
oughly incorporate the salt mottles would not appear in the fin- 
ished butter. 

Drs. Van Slyke and Hart say that if the proteids are thor- 
oughly washed from the butter, mottles cannot be produced, no 
matter how unevenly the salt is distributed. Complete removal 
of the buttermilk by washing is one of the essentials in preventing 
nM)ttles in butter. 

Storch made an extensive study of the causes of mottles 
in butter. He claims that the water in butter is present in 
two forms or conditions. There is the water which is con- 
tained in the form of an extremely fine emulsion in the nitro- 
genous material composing the film surrounding the fat globules; 
and there is the water which is enclosed by the granules as they 
form or is picked up later from the buttermilk or the wash-water, 
and which is present in the finished butter in the form of larger 
droplets, or a much coarser emulsion. The whitish, opaque 
dapples, Storch claims, are due to the fine emulsion of water 
in the nitrogenous material referred to, and the yellow, clearer 
markings to the larger droplets of water picked up from the 
buttermilk and wash- water. 



MOTTLED HU'rTl<:R 2S1 

Sammis and Lcc repeated a portion of Storcli's investiga- 
tion. They found that butter-fat, freed from casein by melting 
and filtration, then emulsified with water and churned, pro- 
duced typical mottles when the salt was not evenly distributed 
throughout the mass. They thus produced mottles entirely 
independent of the casein. Microscopic examination of such 
butter showed similar results as in the case of Storch's experi- 
ment. In the portions which were lighter in color, the water 
was present in the form of innumerable small droplets, while 
in the portions that were darker, the droi)lets of water were much 
larger. No counts nor measurements of the droplets were given. 
These investigators emphasize the importance of thorough 
working of the butter to prevent the mottled appearance. 

The mottles caused by improper incorporation of salt assume 
two different forms, viz., mottles proper, and wavy butter. As 
has been mentioned before, the mottles result from undissolved 
salt. Whenever there is undissolved granular salt present, the 
moisture is attracted and the color deepened at that particular 
place. In case the water has already been saturated with salt, 
there is no danger of mottles, no matter how much gritty salt is 
present. 

Mottles do not affect the quality of butter, but the consuming 
public desire uniformity in color. For this reason butter is 
artificiidly colored during the winter months when cows are 
on dry feed which is not conducive to the production of a yellow 
color in the butter. Many people like the appearance of marble 
cake; the same people would seriously object to marbled butter. 

The salt which is placed on butter or mixed with it has an 
affinity for water. Therefore, the droplets of water are attracted 
to the granules of salt. The result is that a certain portion of 
the butter assumes a dark appearance, possibly somewhat 
similar to the clouds appearing before a rainstorm; or, in other 
words, mottles may be said to be caused by the uneven distribu- 
tion of the water droplets. 

It will be observed that the white streaks in butter contain 
little or no salt. Professor O. F. Hunziker has done very 
extensive work on this subject. The white opaque places in 



282 



SALTING AND WORKING OF BUTTER 



mottled butter are caused by the localization of innumerable 
very small water droplets. 

There are a number of things that have a tendency to cause 
mottles. In the early spring, when the cows are changed from 
dry feed to grass, mottles are more prevalent than at any other 




Fig. io6. — Imperfect working, due to overloading churn, and causing a portion 
of the butter to fall over the rolls without being worked, has a tendency to 
cause mottles and uneven distribution of moisture. 

season of the year. This is due to the presence of an increased 
per cent of the low-melting fats in butter. The butter has a 
tendency to be slushy or soft and the granules of salt appear to 
be imbedded in the butter and do not dissolve as readily. 

This defect may be overcome by churning at a sufficiently 
low temperature. The butter granules will then gather into a 



MOTTLED BUTTER 283 

firm enough mass to be efficiently worked. In small creameries 
where only one or two churnings are to be made the butter can 
be worked enough to mix the salt thoroughly throughout the 
mass and permitted to stand for an hour, when the working may 




Fig. 107. — Imperfect working, due to overloading churn, and causing a portion 
of the butter to fall over the rolls without being worked, has a tendency to 
cause mottles and uneven distribution of moisture. 

be completed. This is a method that has been used by some 
buttermakers for a great many years. 

The system used in Denmark a number of years ago, when one 
of the authors was visiting that country investigating creamery 
conditions, was to mix the salt thoroughly with the butter on 
the table worker ; then cut the butter up into large rolls and place 



284 SALTING AND WORKING OF BUTTER 

it in a tank of water at a temperature of 60° F., and permit it to 
stand there for two hours; then take the butter out and finish 
working it. This had the effect of giving the entire mass of 
butter a uniform temperature and it gave sufficient time to get 
the salt quite thoroughly dissolved before completion of the final 
working. 

Quite a common cause of mottles, particularly in the summer 
months, is the overloading of churns. Part of the butter 
falls over the rolls instead of passing through them. Working 
butter under these conditions will not, as a rule, produce either a 
uniform color or a uniform distribution of moisture. Where the 
rolls are out of alignment it also has a tendency to result in 
uneven working and thus cause mottles. 

Washing the butter with very cold water which chills the 
surface of the granules also has a tendency to produce mottles. 
Butter does not appear mottled when first taken from the churn. 
On standing the more loosely held large water droplets run 
together into larger aggregates and the portions of the butter 
containing these fewer but larger droplets show deeper yellow in 
color. 

Prevention of Mottles in Butter. — To state the cause or causes 
of a defect is often to suggest the remedy or remedies, in a 
large measure. Unsalted butter is never mottled. This is, in 
itself, very suggestive. It is well known to experienced 
creamerymen, and has been taught in our dairy schools for 
years, that butter will be neither mottled nor streaked if the 
salt is thoroughly dissolved and the brine evenly distributed and 
incorporated in fine particles or droplets in the butter by the 
time we are through working it. There are several means which 
further this end, and these may be briefly stated as follows: 

Have the cream at the right temperature for churning. 
The butter will then come in good condition. It will be reason- 
ably firm and the buttermilk can be washed out of it thoroughly. 

Have the wash-water at the right temperature, so that the 
butter will be in good condition for working. It can then be 
worked sufficiently to insure the end sought without injuring the 
grain and body of the butter. 



CURDY SPECKS IN BUTTER 



285 



See that the worker is in good condition. The space between 
the rolls, from end to end of the churn, should be the same; 
they should be properly set and in perfect alignment, and there 
should be no looseness in the bearings and no slipping. The 
rolls should be straight or without any warps in them, and so 
set that the elevations on the one m.eet the grooves of the other. 




Fig. io8. — Rolls out of alignment. 

The same care must be taken with regard to the relation of the 
roll to the shelf in single-roll churns. 

Use a good quahty of salt that will dissolve readily, and 
distribute it in the butter as evenly as possible from end to 
end of the churn. 

Do not make too large a churning. This means overloading 





Fig. 109. — Rolls perfect. 



Fig. 1 10. — Rolls not meshing, causing 
imperfect working. 



the workers, and as a consequence part of the butter falls over 
the rolls and is not worked. 

If mottles develop in butter they can be eliminated by rework- 
ing it. But this is a remedy that it should not be necessary 
to apply very often. 

Curdy Specks in Butter. — Curdy specks are not, properly 
speaking, mottles. We should make a sharp distinction between 



286 SALTING AND WORKING OF BUTTER 

the two. Curdy specks, as the term implies, are small white 
particles of curd throughout the butter that are visible to the 
naked eye. Overripening of either the starter or the cream may, 
and probably will, produce curd particles that will show in the 
butter, especially if the cream is not strained into the churn 
through a fine strainer. Avoid these faulty conditions; break 
up and mix the starter thoroughly before putting it into the 
cream; and strain the starter into the cream and the cream into 
the churn. 

To insure uniform salting it is advisable to bring the butter 
up on the shelf and rolls, make a trench in it from end to end 
of the churn — leaving both ends closed — and distribute the salt 
evenly along the trench. Should the butter be in a very firm 
condition a little water should be added to the salt. The 
trench is then closed so as to cover the butter before the workers 
are started. 

As butter is worked it becomes an aggregation of butter 
granules with the intervening spaces occupied by water, curd and 
air. The more butter is worked the smaller the intervening 
spaces. On the broken surfaces of worked butter and under the 
microscope the water appears in the form of round droplets. 
The less the butter is worked the larger the drops and the more 
ragged the break or grain. The more the butter is worked the 
smaller the droplets of water and the shorter the grain. If the 
working of butter continues, air to the extent of lo per cent or 
less by volume is incorporated. 

When a piece of butter is torn from the partly worked mass 
its broken surface is very irregular and shows large drops of 
water, like tears. Upon squeezing, a shower of water falls out 
of the butter. If packed in this condition the butter would leak. 
As the working progresses the drops become smaller and smaller 
and fewer can be squeezed out of a piece. The working has 
produced the desired end when the broken surface sparkles with 
small droplets of water like pinheads and only two or three drops 
fall out upon squeezing. If packed at this stage the butter has a 
beautiful grain and does not leak; but if worked beyond this 
point the droplets of water disappear, the grain becomes short 



BRINE-SALTING 287 

and the butter becomes greasy, air is incorporated, and the 
color is hght, dull and lusterless. Such butter is overworked 
and keeps poorly. 

The process of working grinds up the water in the butter into 
smaller and smaller drops. In a leaky butter the water is 
present in large drops; in a dry butter it is present in small but 
numerous drops. Repeated working does not injure the grain so 
long as drops of water can be seen on the torn surface. Logically 
the working of butter should be continued until the butter is not 
leaky and stopped before it is dry and sticky. 

Brine-salting. — Brine-salting is not as a rule practiced in 
creameries. It is too expensive a method of salting, and also 
too laborious. By salting butter with brine it is hardly possible 
to get in salt enough to suit the American butter markets, 2 
per cent being about the maximum amount of salt that can be 
incorporated by the brine method. 

In some instances, brine-salting has been recommended. If 
a light mild taste is desired, the brine method may give good 
results. The greatest advantages of brine-salting are that 
mottles in butter are practically avoided, and that the overrun 
is usually increased a trifle. Especially is this so if the tempera- 
ture of the brine is medium high when added to the butter. In 
order to get enough salt (2 per cent) into the butter by the brine 
method, it is necessary to churn it considerably in the brine and 
to use two sets of brine. When brine is first added the butter 
already contains considerable water. This water practically 
has to be replaced by brine. This is difficult to do, especially if 
the butter has been overchurned a trifle. 

Churning the butter in the first brine will soon dilute the brine 
to such an extent that it will impart but httle saltiness to the 
butter. For this reason this first brine should be removed and 
another one added, and the butter churned again in this brine. 
This last brine wifl have very Httle curd in it, and can be saved 
until the following day and then used as the first brine. The 
first brine may be used each day for soaking tubs. 

It is essential to leave the brine on the butter for from five 
to fifteen minutes. Churning excessively in the brine, espe- 



288 SALTING AND WORKING OF BUTTER 

daily if butter is medium soft, will cause too much water to be 
incorporated in the butter. After the butter has been exposed 
to the second brine the proper length of time, it should be drawn 
off and the butter worked in the usual manner. Less working 
is usually given to butter which has been salted by the brine 
method. It should be worked enough to distribute the brine 
evenly in the butter, and to bring the butter into a compact form. 
If the butter salted by the brine method is not worked sufficiently, 
it will become streaky in color after standing. 

SALT TEST 

Principle of the Test. The reagent used is a solution of silver 
nitrate (AgNOs), and the indicator is a solution of potassium 
chromate (K2Cr04). The silver nitrate will combine with 
either common salt (NaCl) or potassium chromate, but it has the 
stronger affinity for salt. Hence, if we add a few drops of the 
potassium chromate to a solution of common salt, and then 
gradually add silver nitrate solution, the silver nitrate will com- 
bine with the salt, forming white or colorless compounds. But 
as soon as the salt is all used or taken up the silver nitrate com- 
bines with the indicator, potassium chromate, producing a 
brick-red compound. 

Chemical Changes that Take Place. — First, as long as there is 
free salt: AgNOs (silver nitrate) -f NaCl (common salt)=AgCl 
(silver chloride) -|-NaNO 3 (sodium nitrate). No colored sub- 
stances formed. Second, after all the salt has been acted upon — 
2AgN03 + K2Cr04 (potassium chromate) = Ag2Cr04 (silver chro- 
mate, brick-red) -F2KN03. Brick-red color produced. 

Proportions in which Silver Nitrate and Salt Combine with 
Each Other.— 

Molecular weight of silver nitrate, 

AgNOs = 108 -F 14 -f3X 16 = 170 

Molecular weight of common salt, 

NaCl = 23 -f35.5 = 58.5 
Both are univalent. 



SALT TEST 289 

Hence, 

58. 5 grams salt combine with 170 grams silver nitrate. 

170 
I gram salt combmes with — r — = 2 . 006 grams silver nitrate, 

58.5 

or 

.01 gram salt combines with .02906 gram silver nitrate. 

Features of Practical Salt Tests. — The same principle applies 
to the various salt tests. In the different practical tests, com- 
binations are worked out which enable us to read the per cent of 
salt directly, without having to make any mathematical calcu- 
lations. 

The following combination enables us to read the per cent 
of salt in butter directly : 

(i) 29.06 ( = 29.0) grams of silver nitrate in a solution made 
up to 1000 c.c. 

(2) Burette for silver nitrate solution graduated in cubic 
centimeters and tenths of a cubic centimeter. 

(3) 10 grams of butter, with the salt solution from it made up 
to 250 c.c. 

(4) 25 c.c. of the salt solution, taken by means of a 25 c.c. 
pipette, that is, a tenth of the salt solution, or a tenth of the salt 
in the lo-gram sample of butter. 

In 1000 c.c. of silver nitrate solution there are 29.06 grams of 
silver nitrate. 

In I c.c. of silver nitrate solution there is .02906 gram silver 
nitrate. 

But we have already shown that .02906 gram silver nitrate 
reacts with .01 gram of salt. 

.01 gram salt in 25 c.c. salt solution = .i gram salt in 250 c.c. 
of salt solution, or in 10 grams butter, which is i per cent 
of salt. 

Hence, each cubic centimeter of the silver nitrate solution 
required in making the test indicates i.o per cent of salt in 
the butter. 



290 SALTING AND WORKING OF BUTTER 

To Make a Salt Test. — Either weigh out lo grams of butter, 
or take the residue from the lo grams of butter used in the mois- 
ture test; and rinse thoroughly into a suitable flask, with a 250 
c.c. mark. on it, using distilled water at a temperature of 110° 
to 120° F. for the purpose, and making up to 250 c.c. with dis- 
tilled water at the same temperature. Mix thoroughly to dis- 
solve all the salt. 

25 c.c. of the salt solution are then transferred to a white 
enamel cup, and to this are added 2 to 3 drops of indicator (a 
10 per cent solution of potassium chromate) from a brown glass 
dropping bottle. 

The silver nitrate solution is then added from a burette, and 
mixed as it is added, until a permanent, light brick-red color 
appears. 

Note the quantity of silver nitrate solution required to 
make the test. If, for example, it requires 2.7 c.c. of silver 
nitrate solution to make the test, this indicates that there is 
2.7 per cent of salt in the butter; if it takes 3.8 c.c. of silver 
nitrate solution, the per cent of salt in the butter is 3.8, etc. 

Note. — If the salt solution were made up to 100 c.c. instead 
of 250 c.c, we could take 10 c.c. instead of 25 c.c. of this solution 
to a test and read the per cent of salt direct, just as above. In 
both cases we take a tenth of the solution or a tenth of the salt 
in the lo-gram sample of butter. 

Another combination that will read the per cent of salt 
directly: 

(i) A tenth normal (N/io) solution of silver nitrate, that is, 
17 grams of silver nitrate in 1000 c.c. of the solution. (The 
molecular weight of silver nitrate being 170, there are 170 grams 
in 1000 c.c. of a normal solution, and a tenth of this in a tenth 
normal solution.) 

(2) 10 grams of butter, the salt in it, being dissolved in 
300 c.c. of water. 

(3) By means of a 17.6 c.c. pipette we take 17.5 c.c. of the 
salt solution to a test. 

Each c.c. of silver nitrate solution required to make the test 
indicates i per cent of salt in the butter. 



WORKING OF BUTTER 291 

Distilled water should be used in making the reagents and 
for the test. The reagents should be kept in brown glass bottles 
and out of strong light. 

It is not advisable to make up more than about a month's 
supply of silver nitrate solution at a time. 

WORKING OF BUTTER 

Objects. — The objects of working butter are: 
(i) To distribute the salt and brine evenly in the butter. 
The number of revolutions in the churn necessary to accom- 
plish this will vary somewhat according to the conditions of 
the butter, and according to the kind of butter- workers employed. 
If the butter is of medium firmness, about twelve revolutions in 
the Victor Combined Churn will usually distribute the salt 
properly, providing the working is well distributed over the 
working period. It used to be, and is still, the practice in 
creameries to add the salt while the butter is in a hard granular 
condition, and then rotate the churn several times in slow gear 
without putting the workers in gear. This is done in order to 
mix the salt thoroughly without working. Then it is allowed 
to stand for five or ten minutes, then worked about four revolu- 
tions and allowed to stand a little while again, then the working 
is completed by allowing the churn to revolve four or five times 
more, or as many as is deemed necessary to bring the butter into 
proper condition. 

It has, however, been demonstrated that it is not advisable 
to add the salt while the butter is in this hard granular form. 
The butter should be united into larger irregular granules before 
the salt is added. If the salt is added to the butter in a more 
or less gathered condition, the workers should be put in gear at 
once, for otherwise the salt will be scattered on the inside of the 
churn. Butter can be worked three or four revolutions and 
then allowed to stand until the salt is almost dissolved, at which 
time the working can be completed by revolving the churn four 
or five revolutions more. Some prefer to work a little more 
than ten revolutions in order to be sure that the salt has been 
evenly distributed. 



292 



SALTING AND WORKING OF BUTTER 



If the Disbrow churn is being used, it is necessary to work 
the butter a greater number of revolutions than that recom- 
mended when the Victor churn is used. In the Victor churn 
the butter is virtually worked twice at every revolution, while 
in the Disbrow churn the butter is only worked once for about 
three-quarters of a revolution. From sixteen to twenty revolu- 
tions of the Disbrow churn usually mix the salt with the butter 
properly. It is impossible to state exactly the number of revo- 




FiG. III. — Old-style table butter- worker. 



lutions butter should be worked, as it varies according to different 
conditions. 

(2) Butter is worked in order to bring it into a compact form. 
When butter is soft it usually gathers, but if it is present in the 
firm granular condition, which condition results from churning 
thin cream and washing the butter in cold water, it is more or 
less difficult to get the little granules together. More working is 
necessary when the butter is in such a condition. 

(3) The working of butter also expresses an excessive amount 



WORKING OF BUTTER 293 

of buttermilk or water that may be present. By adding salt 
and then workilig the butter, the excess of buttermilk is largely 
eliminated. Especially is this so when the butter is in a medium 
firm condition. Working is also effective in removing water 
from the butter. 

Moisture Tests of Butter. — i. Official Method. — "Weigh 1.5 
to 2.5 grams of the sample into a fiat-bottomed dish, having a 
surface of at least 20 sq. cm., dry at the temperature of boiling 
water and weigh at hourly intervals until the weight becomes 
constant. The use of clean dry sand or asbestos is admissible." 

2. Rapid Method. — The moisture tests used in creameries 
differ from the official method^ mainly, in the speedier, less 
refined scales used, and larger sample taken to a test, and in the 
adoption of a higher temperature for driving the moisture off 
more quickly. The results, when the work is carefully done, are 
quite reliable. 

Tj Make a Test. — Obtain an average composite sample from 
the churn, through scraping off the surface of the butter with a 
ladle and taking samples from end to end of the churn by means 
of a dry. warm spatula or spoon. In case of a tub take a core 
with a trier, extending diagonally from top to bottom of the 
package, and make up a composite sample from sections of this. 
The composite sample jar should have a close cover. 

Carefully warm the sample until the butter is of a pasty or 
creamy consistency and mix well with a spatula. 

Weigh 10 grams into a well-dried light aluminum cup about 
2^ in, in diameter. Place the cup on an asbestos sheet over a 
low gas or alcohol-lamp flame, or hold over a low, direct flame. 
Do not heat too rapidly. The heating process is complete when 
foaming ceases and a light-brown color appears, and should not 
be carried beyond this stage. 

Allow the cup and contents to cool, then reweigh. The per- 
centage loss in weight indicates the per cent of moisture. Most 
scales read this direct. 



CHAPTER XIX 



PREPARING BUTTER FOR MARKET AND PREVENTION 

OF MOLD 

In the preparation of butter for market, care should be 
exercised to see that only those woods which will not affect the 
flavor of the butter are used in the package. From practical 





Fig. 112. 



-Elgin style butter- 
tub. 



Fig. 113. — Bradley 
butter-boxes. 



experience and from various experiments it has been found 
that ash and spruce are the most suitable woods in which to pack 
butter to be delivered to the market. In the eastern markets a 
decided preference is given to the 60-pound ash tub. Prior to 
the use of this tub the old-style firkin was used. Possibly the 

294 



PREPARING BUTTER FOR MARKET 



295 



reason for the preference given to the 6o-pound tub in the eastern 
market lies in the fact that many dealers have so arranged their 
refrigerators that they have a space in which the tub fits. Custom, 
based upon long use of the 6o-pound tub, has created such a 
decided preference for butter packed in this manner that it 
will sell in the eastern market at from half a cent to one cent 
more a pound than if packed in a cubical box. 

The Pacific Coast markets, on the other hand, have a decided 





Fig. 114.— The Eureka hand 
butter-printer. 



Folded. 
Fig. 115.— Butter cartons. 



preference for the cubical spruce box, and will pay a premium 
for butter packed in that style. 

If the butter is to be cut into prints, as is done by a 
great many dealers at the present time, the cubical box has an 
advantage over the tub. Butter so packed will cut into prints 
with less waste. 

In addition to spruce for the cubical box. Southern poplar 
has been used quite extensively. A box of the following dimen- 



296 PREPARING BUTTER FOR MARKET 

sions holds 65 pounds of butter, and has given excellent satis- 
faction for packing butter that is to be recut into prints. The 
dimensions are, 14I by 13I by 10^ inches, te inch ends and sides, 
I inch top and bottom. 

For the Pacific Coast trade, boxes holding as much as 90 
pounds are used by some of our larger creameries. Boxes of 
this size are not used to any extent in the eastern markets. 

For packing butter on the farm, earthen jars give excellent 
satisfaction, particularly if they are well glazed. Due to the 
possibility of breakage, such jars are not used to any extent for 
shipping butter. Earthern jars or crocks are very heavy and 
easily broken during transportation. 

For shipping in small packages of different sizes, the spruce 
package is most commonly used. Some tubs manufactured for 
this purpose hold 10, 20 and 30 pounds. The spruce tub is 
also made in larger sizes, holding from 60 to 65 pounds. 

While spruce will not flavor butter if the tub is rightly 
prepared, the disadvantage of the spruce package is that it soils 
very easily on the outside and gives the package an unsightly 
appearance. 

In Canada, New Zealand and Australia the cubical box is 
used exclusively. These boxes are made to hold 56 pounds of 
butter. Sometimes double covers are used. 

Storing Butter in Creameries. — The temperature of the room 
in which butter is stored should be as low as conditions will per- 
mit. In local creameries a temperature of 40° or lower should 
be maintained. In small creameries the butter is usually kept 
at the creamery from three to six days. In some sections of the 
country railroads carry refrigeration cars weekly; in others semi- 
weekly. Hence, it is necessary to store butter at as low a tem- 
perature as possible while it is waiting to be shipped. The 
refrigerator in which the butter is kept at the creamery should be 
as pure and dry as possible. Damp places are favorable to the 
production of molds. Neither vegetables nor foods of other 
kinds should be allowed in the refrigerator with butter, as they 
are likely to impart foreign flavors to it. 

All large creameries, the so-called centralizers, are equipped 



COST OF MANUFACTURING BUTTER 



297 



with mechanical refrigeration for coohng purposes. Hence, 
they are able to keep the storage room for butter at any tem- 
perature desired. On the contrary, many of the small creameries 
have to depend exclusively upon ice for refrigerating purposes. 




Fig. ii6. — Tub-fasteners; common tins. 



In cases where ice is not available, water can be utilized for the 
purpose of cooling. Water in the creamery can be forced through 
galvanized iron tanks, which are properly placed in the butter 
storage room or refrigerator so as to allow as much cooling sur- 




FiG. 117.— Tub-fasteners: tin and tack combined. 

face in the butter room as possible. This is merely a makeshift 
for ice and will not cool the room so effectively, but in the absence 
of ice this is better than no cooling at all. 

Cost of Manufacturing Butter. — This will depend upon the 



">to 



y 



Fig. 118. — ^Tub-fasteners; riveted. 

volume of cream received and the kind of packages in which the 
butter is to be packed for market. About fifteen years ago the 
Iowa State Dairy Commissioner investigated this question, and 
found the cost of manufacturing ranged from 1.2 cents to 6 
cents per pound. The creamery where the cost ran up to 6 



298 



PREPARING BUTTER FOR MARKET 



cents a pound only produced 30,000 pounds of butter per year. 
The lowest cost of manufacturing was submitted by a co-opera- 
tive creamery making nearly half a million pounds of butter 
from whole milk exclusively. The approximate average cost of 
making butter for the creameries in the State of Iowa at that 
time was 2j cents a pound. As labor, coal and all material used 
in the manufacture of butter have greatly advanced, the cost at 
the present time in the small creameries will exceed the above 
figures. 

In a medium-sized central plant the cost should not exceed 

2 cents a pound. This does not 
include the package. It includes 
the cost of factory suppHes, such 
as salt, butter-coloring, milk for 
starters, power, labor, refrigeration, 
factory incidentals, factory main- 
tenance and depreciation. The 
cost of package will depend en- 





FiG. 119. — Friday printer. 
(J. G. Cherry Co.). 



Fig. 120. — Friday box. 



tirely upon the kind of package used and the labor necessary to 
pack. If the package used is the 60 or 65 pound tub or cubical 
box, the cost of package and labor involved will not be very 
great. If the butter is to be put up in fourth-pound or pound 
prints, the cost will be much greater. At the present time, the 
authors would place the cost, with the package included, at 3 to 
3I cents per pound. 



COST OF MANUFACTURING BUTTER 



299 



During the fall and winter, many creameries where the 
milk supply is rather low print all their butter. Many of the 
commission men will pay a premium of i cent a pound for butter 




Fig. 121. — Miller hydraulic cutter for hard and frozen butter. (L. C. Sharp 

Mfg. Co.). 

SO packed. The butter-maker has more time at this period 
and should take advantage of it to put his butter up in neatly 
packed prints. A creamery should have its own wrapper, and 



Dead Air Space 




w/m////m///////////////////////Mm/ 

Fig. 122. — Cross-section of a sewage-disposal tank. (Wallace's Farmer.) 

it should bear the name of the manufacturer. If the butter is 
good, it will take but a short time for the consumer to become 
familiar with this brand and a demand for it will eventually be 



300 



PREPARING BUTTER FOR MARKET 



created. It is essential, however, that we consider the cost of 
printing the butter and the loss in printing. Some little waste of 
butter accompanies the printing process. Butter to be printed 
nicely should be firm but not hard, so that the print may assume 
its proper shape. Butter should be worked to a point where it is 
free from loose moisture; otherwise, the loss will be much heavier 
in printing. 

Treatment of Tubs and Boxes. — Investigations were made by 
Rogers ^ of the different treatments of tubs for the prevention 



Air Inlet 
D 




Fig. 123. — Septic tank for creamery sewage disposal. (By Prof. J. Michels.) 
The tank should be located in the ground with the top within a foot or 
two of the surface. It may be constructed of planks. Brick, stone, or 
concrete is preferable for durability. The tank should be built air-tight 
except in two places, D and E, 



of contamination by mold. Comparison was made of the fol- 
lowing methods: 

(i) Soaking the tubs overnight in cold water. 

(2) Boiling five minutes in a saturated brine solution and 
leaving in the brine overnight. 

(3) Soaking overnight in a brine containing 9 per cent of 
commercial formalin (which is a 40 per cent solution of formalde- 
hyde). 

(4) Coating the tubs on the inside with paraffin. 

(5) Immersing the tubs for a few seconds in paraffin at a 
temperature of 250° to 260° F. 

Rogers comments upon the table giving results of his investi- 
gations and makes some general observations, as follows: 

1 Bulletin 89, Bureau of Animal Husbandry, U. S. Dept. of Agriculture. 



TREATMENT OF TUBS AND BOXES 



301 




I IQ. 

1« ,tZ X SI 



.1. 




302 PREPARING BUTTER FOR MARKET 

" It will be seen from this table that all of the untreated 
tubs became moldy. Of the six tubs treated with hot brine, 
one was badly molded, one was slightly molded and one had 
mold on the outside. Of the six tubs soaked in the brine- 
formaldehyde mixture, one was badly molded. None of the 
tubs coated with paraffin showed any mold whatever, and the 
same was true of those dipped in paraffin. 

" To treat tubs by the brine-formaldehyde method or the 
hot-brine method a vat should be made large enough to hold 
submerged the tubs used in one day. The cost of either of these 
two methods is insignificant as the bath may be used repeatedly. 
The objections to these two methods, in addition to their inef- 
ficiency, would probably be found in the discoloring of the wood 
and, with the hot brine, in the excessive weight and swelhng of 
the tub." 

Paraffining of Tubs. — From the investigations made it would 
seem that the most efficient method of treating tubs or boxes 
for the prevention of mold is to paraffin them on the inside. 

Before tubs are paraffined they should be thoroughly 
steamed. In extreme cases, where tubs are very open, it may 
be necessary to soak them, but only in such cases. Whether 
soaked or not,. the tubs should be steamed just before paraffining 
them. This swells and tightens the tub, and heats the wood and 
opens its pores so that the parafhn will penetrate it sufficiently 
and at the same time form a nice, smooth coating. The par- 
affin should be heated to a temperature of about 250° F. If 
much below this it is apt to cause the coating to be thick and 
patchy, and if much above it is likely to soak into the wood and 
not form a proper coating. The easiest way to heat the paraffin 
in a creamery is to place a steam coil in the bottom of the 
paraffin tank with a valve or dripcock on it to allow the escape 
of condensed steam. 

Where the work is done in a small way, the paraffin can be 
applied in one of two ways — either by means of a brush or by 
pouring some paraffin into the tub, rotating it to cover the whole 
surface and then placing it mouth downward to drain the sur- 
plus paraffin from it. But in a creamery of any size a suitable 



PARAFFINING TUBS REDUCES LOSS FROM SHRINKAGE 303 



apparatus for spraying the inside of the tub with parafHn 
should be used. 

As it only requires about 3 ounces of paraffin for a tub that 
holds 60 to 65 pounds of butter the cost is not great, and the 
work entailed in paraffining is no greater than that of either of 
the other treatments mentioned. 

Paraffin furnishes no food for molds; if there be any mold 
organisms on the wood 
they will probably be de- 
stroyed to a very great 
extent, if not entirely, 
either by the hot paraffin 
spray or through the ex- 
clusion of the air which 
they require for growth; 
and, even faihng this, 
the coating of paraffin 
shuts them off from the 
parchment paper and the 
butter. Furthermore, as 
paraffin is impervious to 
water, the space between the liner and the tub remains filled 
with water or brine which excludes the air and retards or pre- 
vents the development of any molds that may be present. 

Paraffining Tubs Reduces Loss from Shrinkage. — Another 
strong inducement to paraffin tubs is the saving in shrinkage, 
due to the prevention of the escape of moisture. In an experi- 
ment made by Rogers, during his investigations, he found the 
shrinkage, during a period of eight days in creamery storage 
and in transit, on butter packed in paraffined tubs and in tubs 
soaked in brine, respectively, to be as follows: 




Fig. 125. — Tub paraffiner. (Creamery 
Package Mfg. Co.). 



Treatment of Tubs 


j Weight of Butter 
Number of 1 (Pounds) 


Shrinkage 
Pounds 


^"•^^ When Packed After Eight 
Days 


Parafi&ned 


12 7S7f 756 if 

12 . 766I i 71^0 7t 


Soaked 






' * 



304 PREPARING BUTTER FOR MARKET 

Thus the saving in shrinkage, through paraffining, was 
6 pounds on 12 tubs or half a pound per tub. 

With unsoaked, paraffined tubs the tare should be marked 
on the package. Such tubs may be as much as 2 pounds Hghter 
than soaked tubs. 

Treatment of Parchment Paper. — As parchment paper is a 
good medium for the growth of mold organisms and may harbor 
the spores, though showing no growth of mold, it is quite as 
important to treat it as to treat the tubs for the prevention of 
mold. One method of treatment for parchment paper is to 
soak it for at least ten minutes, before using, in a saturated 
solution of brine at or near the boiling point. Russell and Hast- 
ings ^ say, " A most efficient way of treating paper, either for 
tub liners or print wrappers, is to place same in boiling water for 
a few minutes." As formalin is very destructive of mold, 
another very efficient treatment for parchment paper is to soak 
it in cold brine or water containing formalin. 

YEASTS AND MOLDS IN BUTTER 

Bacteria are not the only micro-organisms found in milk and 
its products. There are also yeasts and molds, the mold most 
commonly found being Oidium (plural Oidia) lactis, or the 
ordinary white mold which frequently appears on the surface 
of sour milk or cream. 

What may be desirable in connection with one dairy product 
may be the reverse with regard to another. For instance, 
Freudenreich and Marchel have shown that in the ripening of 
certain Swiss and Belgian soft cheeses the common white mold 
(Oidium lactis) plays a principal part. In these products its 
presence is not only desirable but necessary. 

On the other hand, it is found that where yeasts and molds 
are present to any considerable extent in butter, it is not nearly 
so likely to possess good keeping qualities as if they were not 
present, even though its flavor when made be quite satisfactory. 
They may be present in cream in quite large numbers, when it 

1 Dairy Bacteriology. 



YEASTS AND MOLDS IN BUTTER 305 

arrives at the creamery, but if it be efficiently pasteurized and 
kept from subsequent contamination, the mere fact of their 
presence in the raw cream does not mean that the butter made 
from this cream will be either defective in flavor, when made, or 
lacking in keeping quality. 

A study, by Bouska and Brown, of a large number of pack- 
ages of butter placed in cold storage showed that the number of 
yeasts and molds present in butter, when made, is a fair cri- 
terion from which to judge of its keeping quality. To put it 
in another way, the number of yeasts and molds present in 
butter, as it comes from the churn, is a good indication as to the 
efficiency of pasteurization and the subsequent handling of the 
cream to prevent re-contamination. 

The laboratory of the American Association of Creamery 
Butter Manufacturers has, for a number of years, made counts 
of the number of yeasts and molds in samples of butter sent in 
by its members, for this purpose. As a result of this work, and 
the advice and assistance given, many of the creameries have so 
improved their methods and equipment as to practically elim- 
inate yeasts and molds from their butter, and make a product 
possessing good flavor when fresh and good keeping qualities. 

Where the number of yeasts and molds in butter is reduced 
to ten or less per cubic centimeter — colonies counted without the 
aid of a magnifying glass — this is regarded as excellent work; 
and several of the creameries have reached this stage of effi- 
ciency. A strong effort should be made by every creamery to 
keep the number of yeasts and molds as low as possible, that is, 
to thoroughly pasteurize the cream and prevent subsequent 
contamination. 

Whether or not the yeasts and molds present in butter are a 
direct cause of deterioration is not definitely known, although 
there are reasons for believing that this is not necessarily so. 
Hastings found yeasts to be present in butter which won first 
prize in a Wisconsin educational contest. The presence in 
butter of yeasts and molds in large numbers usually means the 
presence of other undesirable organisms in the cream, due to 
one or more of the following causes: 



306 PREPARING BUTTER EOR MARKET 

(i) Inefficient pasteurization, the pasteurizing temperature 
being too low or not maintained througliout the run, or some of 
the cream at the beginning or end of a run not being pasteurized. 

(2) Lack of thorough cleansing or sterilizing of the utensils 
and conduits — pumps, vats, faucets, pipes, churns, etc. 

(3) Tho use of a defective starter — one that has become 
contaminated with yeasts, molds and undesirable bacteria. 
Once this occurs it will propagate itself from day to day until 
there is a change of mother-starter. 

It must be remembered that although the pasteurizing may 
be thoroughly done its good effects may be largely nullified 
through subsequent contamination. Hence the fmal test of 
the elliciency of pasteurization, in creamery work, should really 
be the freedom of the butter from the ferments which cannot 
fail to be eliminated by proper pasteurization, and the processes 
that should accompany it. Another test of the thoroughness 
of the pasteurization of milk or cream for butter-making pur- 
poses is the Storch test, which is outlined in the chapter on 
Pasteurization. 

MOLD ON BUTTER 

The development of mold on butter constitutes a defect that 
causes large losses. Mold not only greatl}- mars the appearance 
of a package of butter but affects its flavor as well. It develops 
not only on the outside of butter but along the surfaces of any 
crevices or pockets there may be and works its way into the 
butter. Upon this point we quote Thom and Shaw of the U. S. 
Department of Agriculture:' " In closed packages, wet or 
damp cellars, or carelessly packed masses witli cracks or fis- 
sures in which moisture collects, mold may seriously injure the 
appearance of butter packages or actually induce great changes 
in the butter itself." No score is given to moldy butter. 

As to the character of butter that affords the most favorable 
conditions for the growth and development of mold organisms, 
if any be present, these same authorities say, " Excess of curd 

1" Moldiness in Bullcr," Journal of Agricultural Rcscaroli, Vol. Til, No. 4. 



MOLD ON lUJ'I'I'I'lK 307 

fiivors mold prowlli. Wcll-waslicd hiidcr Is less siil)jc(l. to 
mold. Leaky huUcr butler from wliieli water or hutterniilk 
exudes and collects in the wrappinj^s or the container lur- 
nishes the best conditions lor llic be^dnnin/^ of mold j^n-owlli. 
From these wet areas colonies may spread lo I lie bnllcr ilself." 
These facts j)oinl lo llie necessity of cliurninj^ a.t the rij^hl tem- 
perature, washing' (he bullcr properly with waler al the riji;ht 
temperature and properly workinji; it, so as to free the biiltei- of 
excess of curdy matter and buttermilk and make a butter that 
is not porous but close, and in which the moisture is incorporated 
in fme particles instead of \-drfrvr droplets. They also show the 
importance of |)a,ckinj^f butler closely so as to ivw it of air |)o(k('ts 
and fissures. 

Conditions Favorable to the Growth of Molds.. Like all 
other |)lants, large and small, molds require certain conditions 
for growth. They differ from ordinary plants in that they do 
not require light for their growth, but grow ra,lher better in tlu- 
absence of light. Tlu^y require suitabh; food, but fmd this in or 
on almost a,ny organic ma,lt(U', a,nima.l or vegeta,ble, such a,s 
bread, meat, leather, cheese, etc. They require moisture, and 
hence develoj) rapidly in dam]) rooms and on damp surfaces. 
They require a certain amount of air and will not grow in the 
absence of it. As to temperature, while they develop most 
rapidly in a reasonably wa,rm a,tniospiiere, many of them can 
accommodate themselves to a, wide range of t('mperature. 

Discolorations. The colors |)rodii(c(l by molds ra.nge from 
such light colors as ora,iige-yellow to such dark colors as green, a 
smudg(;d or smoke color and black, according to the type of mold 
present. 

Propagation of Molds. Molds reproduce themselves by 
means of buds (conidia) and sjjores, and these float so freely 
in the a,ir that practically no exposed surfa,ce is entirely free of 
them, and a,ll they need for development, is liu; suitable condi- 
tions we have aJready out lined. 

Sources of Mold on Butter. The two most common sources 
of mold on butter are the tubs or boxes in which it is ])a.(:ke(l 
and the pa,rchment pa,p(,'r. Wood tha.t is green, sappy or dam[) 



308 PREPARING BUTTER FOR MARKET 

is a good medium for the growth of mold; so also is parchment 
paper, particularly if it be at all damp. Hence the tubs should 
be made of well-seasoned wood of good quahty, and both the 
tubs and the parchment paper should be kept in a clean, dry 
place. In the planing of the tub staves the planer should be 
sufficiently sharp to insure a smooth surface. 



CHAPTER XX 

THE COMPOSITION OF BUTTER AND FACTORS THAT 
INFLUENCE ITS CONTROL 

Acts and Rulings as to Composition of Butter. — We have 
only one Federal statute that deals specifically with the com- 
position of butter, and this applies only to the District of 
Columbia. This Act was approved March 2, 1895, and requires 
that butter must contain 83 per cent of milk-fat, not more than 
12 per cent of water and not more than 5 per cent of salt. 

No attempt has been made to enforce the above statute, no 
doubt due to the fact that creameries could not comply with the 
same under the ordinary methods of butter-making. 

Act of August 2, 1886, defines butter as follows: 

" That for the purpose of this Act the word * butter ' shall 
be understood to mean the food product usually known as butter, 
and which is made exclusively from milk or cream, or both, 
with or without common salt, and with or without additional 
coloring matter." 

Act of May 9, 1902, known as the "adulterated" law, reads 
as follows: " Adulterated butter " is hereby defined to mean a 
grade of butter produced by mixing, reworking, rechurning in 
milk or cream, refining, or in any way producing a uniform, 
purified, or improved product from different lots or parcels of 
melted or unmelted butter or butter-fat, in which any acid, 
alkali, chemical, or any substance whatever is introduced or 
used for the purpose or with the effect of deodorizing or remov- 
ing therefrom rancidity, or any butter-fat with which there is 
mixed any substance foreign to butter as herein defined, with 
intent or effect of cheapening in cost the product or any butter 
in the manufacture or manipulation of which any process or 

309 



310 



COMPOSITION OF BUTTER 



material is used with intent or effect of causing the absorption 
of abnormal quantities of water, milk, or cream; that " process 
butter " or " renovated butter " is hereby defined to mean 
butter which has been subjected to any process by which it is 
melted, clarified or refined and made to resemble genuine butter, 
always excepting ' adulterated butter ' as defined by this 
Act." 

The ruling made by the Secretary of the Treasury, the Sec- 
retary of Agriculture and the Secretary of Labor fixes the legal 
standard of moisture in butter as 15.99 per cent. According to 

this ruling, butter that contains 16 
per cent would be classified as adul- 
terated butter. No allowance is 
made for chemical errors in testing. 
While the chemists allow .2 per cent 
for error, the Internal Revenue, in 
enforcing this ruling, makes no such 
allowance. In some districts the 
courts have sustained the Internal 
Revenue Department; in other dis- 
tricts they have not. Some judges 
have ruled that the Congress of the 
United States is the only body that 
has the power to fix definite stand- 
ards for food products. No doubt 
the Act of May 9, 1902, refers to 
methods that were used at that time for the purpose of incor- 
porating abnormal quantities of water. 

Compounds for Increasing Yield of Butter. — The Internal 
Revenue ruling is based entirely upon the " adulterated " 
act. Prior to the adoption of the law of 1902 no attempt was 
made by the government to enforce any regulations concerning 
the manufacture of butter. At this early period various com- 
pounds were used for increasing the yield of butter. 

In 1893 the United States Department of Agriculture pub- 
lished Farmer's Bulletin No. 12, '' Nostrums for Increasing 
Yield of Butter," by Dr. H. W. Wiley, Chief of the Bureau of 




Fig. 126. — Ice-crusher. 



NEED FOR REGULATIONS 311 

Chemistry. The analyses pubHshed in this bulletin reveal the 
fact that the compounds used increased the yield of butter. 
Analyses reported by Dr. Wiley: 

Water Fat Ash (Salt) Casein 

49-55 45-45 i-34 Z-S^ 

31-93 67.30 .15 .63 

In 1900 experiments were carried on by Dr. J. B. Weems 
and Prof. F. W. Bouska at the Iowa Experiment Station. 
They tested out a number of compounds for increasing the yield 
of butter and got the following results: 

Water Fat Ash (Salt) Casein 

41-54 53-04 2.46 2.96 

The second recipe was composed of the following ingredients : 

Alumnae pot. sul 4 ounces 

Gum acacia pure i ounce 

Sacc. lact 2 ounces 2 drachms 

Pure pepsin 5 grains 

Giving butter of the following composition: 

Water Fat Casein Ash (Salt) 

49.64 41.46 5.06 3.84 

In addition to the above, samples of suspicious butter were 
sent to the Station from a Chicago Commission House, which 
showed, 

Water Fat Casein Ash 

59.61 21.31 11.72 7.36 

42.76 44-92 5.10 7.22 

Need for Regulations. — From the above it would seem that 
there was a necessity for some definite regulations concerning 
the standard or composition of butter. Possibly the Internal 
Revenue people, in endeavoring to enforce their ruling of 15.99 
per cent, have been rather exacting in some cases where prosecu- 
tions have been made. 

In many cases, where the butter was found to slightly exceed 



312 C(JJVIP()Sri'l()N OI' IJUTTIOR 

the limit sot by the Internal Revenue Department, creameries 
were assessed lo cents a pound tax on the butter, $50.00 a 
month license, or $600.00 a year, and an additional 50 per cent 
for not taking out a license. In some of these cases a few pounds 
of butter were seized from a churning. Many creameries have 
paid these assessments to avoid the notoriety of going into the 
courts and defending their rights. Not only did the creamery 
pay the above tax, but the dealer in butter was assessed $480.00 
for a year's license for handling so-called adulterated butter. 
Creameries cannot sue the government for the refund of this 
money. The only way they can get into the courts is to sue the 
local agent. In many cases that have come up in the courts, 
expert butter-makers have appeared as witnesses, some in 
behalf of the government and some in behalf of the creameries. 
Some butter experts have made affidavits that the composition 
of butter can be controlled and others have made affidavits that 
it cannot be controlled. This diversity of opinion among so- 
called experts no doubt has been due to lack of experience on 
the part of some of the men testifying. No doubt all wit- 
nesses appearing were honest in the testimony given. 

Control of Moisture in Butter. — After spending over thirty 
years in the butter business in various capacities and conducting 
a vast amount of experimental work in an endeavor to control 
the composition of butter the authors are convinced that the 
moisture-content of butter cannot be completely controlled at 
all times. Extensive investigational work was carried on at the 
Iowa Experiment Station on this subject from 1901 to 1903. 
The object of this work was not to incorporate water in butter 
but to get butter to run uniform in composition throughout the 
year. Prior to this investigational work the senior author had a 
number of analyses made of the butter produced in some of the 
best creameries during the entire year. In this investigation 
the fat-content, the moisture-content and the salt-content were 
found to vary greatly. In the winter months the moisture- 
content might be as low as 10 per cent, and in the summer 
months as high as 17 per cent. These creameries were not 
making any effort to control the composition of their butter. 




Fig. 127. — Rubber nio[). 



CON'J'ROL OF MOISTURE IN BUTTER 313 

Tlicy had their cream in such a condition that it would churn in 
about forty-hvc minutes and the butter granules would be so 
firm that the butter could be worked suihciently to prevent 
mottles and leaky butter. 
Butter was churned nor- 
mally to granules about 
as large as wheat. A 
number of conditions was 
responsible for this wide 
variation in the composi- 
tion from season to season, such as washing with too cold 
water in the winter months and churning at too high a tem- 
perature in the summer months. 

Feeding cows on dry feed during the winter months has an 
effect upon the composition of fats. There are more of the 
high-melting fats present; consequently, the butter has a 
higher melting point. 

In the early days of the creamery business practically all 
butter was worked on the table worker. It was the custom of 
many makers to work their butter twice. After having the 
salt incorporated they would set it in the cooler for three or four 
hours or leave ic until the next day. This had a tendency 
to make butter with a lower moisture-content, as the second 
working would invariably start a fresh flow of moisture from 
the butter. 

The invention of the combined churn and other modern 
creamery machinery enabled the buttcr-niaker more easily to 
control the composition of the butter. The combined churn 
has been a great benefit to the creamery industry. It keeps the 
butter in a more sanitary condition and prevents flies and dirt 
from coming in contact with it. The butter can be worked in 
one working so that it will be free from mottles and in a con- 
dition to be packed directly in sanitary packages. Hence it is 
not surprising that the combined churn is being universally 
adopted throughout the dairy world. 

It is only reasonable to suppose that since the adoption of 
the combined churn the moisture-content of butter would run 



314 COMPOSITION OF BUTTER 

somewhat higher than under the old method of working on the 
table worker, due to the variation of temperature, which affected 
the hardness of the butter when it received its second working. 

Many of the earlier analyses were of butter that had been 
manufactured under the earlier conditions outlined here. 
Hence, it is not surprising that the composition varied greatly. 

The composition of butter may vary greatly in different 
localities. There are two instances that have come under the 
observation of one of the authors; these will be designated as 
Creamery A and Creamery B. Both creameries were located 
in the northern part of Iowa. 

Creamery A in the latter part of the month of May, 1908, 
sent word to the Iowa Experiment Station that they were 
unable to keep the moisture-content of their butter below 

16 per cent. Hence, they naturally feared that their butter 
would be seized by the Internal Revenue authorities, and that 
they would be prosecuted for making adulterated butter. They 
maintained they had had some butter experts there to help them 
out but that they had failed to accomplish the desired results. 

The authorities of the Iowa Experiment Station sent them a 
graduate of the school, Mr. C. L. Mitchel, who had had a great 
deal of practical experience before going to college. He found 
that the butter-maker was churning at as low a temperature as 
44° F., and was trying every method that he knew of to hold the 
moisture below 15.99 P^"^ cent, the limit fixed by the Internal 
Revenue Department. Mr. Mitchel churned out two churnings 
at the same temperature and got a moisture-content of betv^^een 

17 and 18 per cent. He therefore changed his methods and 
raised the temperature to 52° F., and after completing his 
churning worked the butter through the rolls several times to 
expel a portion of the moisture before applying the salt. This 
method worked out very successfully. The rolls expelled con- 
siderable moisture before the salt was applied. As soon as the 
salt was applied it attracted the moisture and the result was 
that sufficient moisture was easily expelled from the butter to 
enable him to make butter that contained moisture below the 
required standard. This method is now practiced in some of the 



ANALYSES OF COMMERCIAL BUTTER 315 

large creameries, especially in the early spring months when the 
grass is inclined to be slushy and wet. Butter of this character 
has a tendency, however, to be slightly greasy or overworked. 

Creamery B was situated in the northwestern part of the state. 
Mr. J. C. Joslyn, who is generally recognized as one of our lead- 
ing butter authorities, had charge of this plant. Prior to the 
experience that Mr. Joslyn had with this high moisture he was 
under the impression that if any butter contained more than 
1 6 per cent moisture, this excess moisture was intentionally 
worked in by the maker. One day, however, he had a churning 
where the method as far as he knew was similar to that he had 
been pursuing to make the best butter. This particular churning 
of butter, upon testing, showed a moisture-content of i8 per cent. 
The peculiar thing about this butter was that the moisture was 
so incorporated that he was unable to expel it, even by reworking 
the butter. The authors have heard of only a few instances of 
this kind. The only way whereby Mr. Joslyn succeeded in 
reducing the moisture was to put the butter in a cooler for two 
days and then break it up into small pieces and rework it. In 
this way he was able to reduce the moisture below the point 
permitted by the government regulation. 

One of the authors, in visiting the Experiment Station at 
Copenhagen, was informed by Dr. Holmes, Dr. Storch's first 
assistant, that they had found in their educational scoring 
contest in Denmark a few firkins of butter that ran as high as 
1 8 per cent moisture and were perfect in body and general 
appearance. They were unable to give any explanation for the 
occasional production of a churning of this kind. The finding of 
excessive moisture in butter is not a new experience in the butter 
business. 

ANALYSES OF COMMERCIAL BUTTER PUBLISHED BETWEEN 
THIRTY AND FORTY YEARS AGO 

Blyth says: 

" There is no standard followed or fixed with regard to the 
percentage of water. In those cases in which the fat is below 
So per cent, the deficiency of fat is usually from excess of water. 



316 



COMPOSITION OF BUTTER 



and seeing the variable quantity of water found in butter, it 
is wisest not to certify on the grounds of water alone unless there 
is sufficient to lower the percentage of fat below 80 per cent. 

" At the Bath Police Court (January, 1879), ^ dairyman had 
been summoned for selling butter, the proximate analysis of which 
showed a considerable addition of water. An appeal to the 
Somerset House elicited the following certificate: 

" We hereby certify that we have analyzed the butter and 
declare the result of our analysis to be as follows : 

Per Cent 

Water 23 . 27 

Butter-fat 74 • 69 

Salt -.78 

Curd 1.26 

" The result of our analyses of numerous samples of ordinary 
commercial butter obtained from different parts of the country, 
including the south of England, shows that the portion of water 
is very variable and that it occasionally amounts to as much as 
19 per cent." 

James Bell obtained, for 117 samples of butter collected in 
various parts of the kingdom, and asserted by him to be genuine, 
proportions of water varying from 4.15 to 20.75 P^^ cent. 

Lewkowitsch in his work says : 

" The proportion of water in butter should not exceed 16 
per cent." 

He gives the following table to illustrate the amount of 
water present in butter on the English market : 





No. of 

Samples 

Examined 


Samples C 
Per Cent 

From 
II to 14 


'ontaining 
of Water 

From 
10 to 16 


Above 
16 


Observer 


English and foreign . 

English 

Foreign 


560 
143 
417 


83.8 
70.7 
88.2 


94.2 

85-4 
97.2 


• 9 

•7 

I.O 


Vieth 

H. D. Richmond 

H D Richmond 







ANALYSES OF COMMERCIAL BUTTER 317 

The above analyses reveal the fact that the moisture-content 
of butter was as high and as variable as at the present time. 
Even at that early date Blyth fixed 80 per cent as the minimum 
fat-content for butter. The composition of butter in the early 
days was more variable than it is at the present time. This is 
to be expected from the fact that more efficient machinery and 
methods are now used for controlling the temperatures, and that 
butter-makers have a better understanding of the effect of tem- 
perature on the control of moisture. Butter made at the present 
time will undoubtedly compare very favorably with butter 
made in earlier years. 

Standards in Different Countries. — Most of the European 
countries have limited regulations to specifying the moisture- 
content of butter rather than the fat-content. The Inter- 
national Dairy Congress held in Brussels in 19 10 passed resolu- 
tions favoring 18 per cent moisture as the maximum amount. 
England has a 16 per cent moisture regulation for butter, and 
24 per cent for blended butter. France has an 18 per cent regu- 
lation and Belgium an 18 per cent regulation for moisture. 
Denmark has a 16 per cent regulation for export and 20 per cent 
for home consumption. Canada has a 16 per cent regulation. 
Germany has an 18 per cent regulation for moisture for unsalted 
butter; for salted butter her standard requires 80 per cent fat 
and not more than 16 per cent moisture. Italy has an 82 per 
cent fat regulation. Queensland has a 16 per cent moisture regu- 
lation and 80 per cent fat. Victoria has an 80 per cent fat and 
16 per cent moisture regulation. 

Possibly the reason that some of the European countries have 
adopted a moisture rather than a fat standard is that it is much 
easier to make a moisture determination than a fat determina- 
tion, as in dealing with moisture we are only dealing with one 
agent, and with the fat determination we have three agents 
to deal with, the salt, casein and moisture. A 16 per cent 
moisture and an 80 per cent fat standard for butter would be 
practically the same. Taking 3 per cent for salt and i per cent 
for casein, this would leave 80 per cent fat, providing the moisture . 
were carried to the limit, which is not a wise or a safe proposition. 



318 COMPOSITION OF BUTTER 

The consumer in purchasing butter buys it for its food value 
or fat-content. Therefore, it is only reasonable that the cream- 
erymen should be willing to have all their butter contain at 
least 80 per cent fat. No doubt the reason so many of the 
European countries have recommended a high moisture-content 
of 18 per cent is that they use less salt in their butter. An 18 
per cent moisture, according to their methods of salting, would 
be about the same as 16 per cent in this country. 

The authors are very much in favor of a definite standard 
for butter, the minimum fat-content being 80 per cent and 
the moisture-content 16 per cent. Some tolerance or allow- 
ance seem.s necessary, as butter may vary in moisture, especially 
from one end of the churn to the other, as much as i or i^ per cent. 

Factors that Aid in Moisture Control. — The two principal 
factors that aid in the control of moisture in butter are the per 
cent of fat in the cream and the temperature at which the cream 
is churned. Where the fat runs uniform and the cream contains 
a high per cent of fat, the moisture can be controlled quite 
accurately by observing the size of the granule and controlHng 
the temperature of churning. 

Bulletin No. loi of the Iowa Experiment Station, page 167, 
gives the results of some churnings made by the senior author in a 
demonstration to short-course students during the month of 
January, 1908. This butter was worked in a Victory churn. 
The cream for these particular churnings was separated from 
whole milk by the Randall Creamery Company, Randall, Iowa, 
and shipped to the Iowa Experiment Station. Upon arrival 
the cream tested from 42 to 45 per cent. After reducing with a 
starter, holding the cream over night and churning the next 
morning, the results given in the accompanying table were 
obtained. 

Butter proper contains, besides the water, fat, protein and 
curd, a small amount of milk-sugar, .35 per cent, and ash from 
.14 to .16 per cent. A butter-maker, to be successful, must 
study his conditions from day to day and from week to week; 
otherwise, during a rainy season when the grass becomes slushy, 
the moisture-content is likely to vary or exceed the limit, even 



FACTORS THAT AID IN MOISTURE CONTROL 



319 



Date 


Churn 


Lbs. of 
Cream 


Per 
Cent 
Test 


But- 
ter- 
Fat 


Churn 
Tem- 
pera- 
ture 


But- 
ter- 
milk 
Temp. 


Tem- 
pera- 
ture 
of 
Spray 


Rev. 
for 
Salt 


Amt. 

of 

Butter 


Per 
Cent 
Over 

run 


Per 
Cent 
Water 


Dec. 31 

Jan 3 
Jan. 6 
Jan. 7 
Jan. 10 


Vic. 
• Vic. 
Vic. 
Vic. 
Vic. 


1283 
1343 
1435 
1204 
910 


32. 5 
36.5 
34-S 

33. S 

33 


412 
490 
49 s 
403 
300 


58 
S8 
57 
57 
S7 


59 
59 
58 
58 
58 


54 
S3 

54 
54 
58 


14 
13 
13 
13 
18 


518 
600 
609 
499 
375 


22 

22.5 

23 

23 

24 


15.8 
15.9 
IS. 3 
15.9 
15.7 



though the same regulations have been observed as at other 
times. Makers have been heard to say that they could control 
the moisture-content of butter to within two or three hundredths 
of the limit. Serious doubts may be entertained as to the cor- 
rectness of such a statement. 

Not very long ago a butter-maker called at the office of the 
American Association of Creamery Butter Manufacturers and 
proclaimed that he was churning in such a way that his moisture- 
content would not vary more than two or three hundredths of a 
per cent from day to day. He was asked to send a sample of his 
butter to the Association laboratory, and it was found to have a 
moisture-content of nearly 17 per cent. The moisture in the 
samples he sent in varied 2 per cent, or ranged from 15 to 17 
per cent. 

Different methods are used for controlling moisture. Some 
make a moisture test when the working of the butter is about 
half finished. If it is found that the butter runs low in moisture 
they add to the churn the amount of water they wish to incor- 
porate and continue working until the butter takes up the water 
added to it in the churn. On the contrary, if they find the 
moisture is too high they fasten the churn door so that moisture 
will escape and continue to work the butter until it contains the 
right per cent of moisture. 

Other companies that manufacture enormous quantities of 
butter never work butter in water. They endeavor to control 
the moisture entirely through their methods of churning. They 
are not, however, trying to crowd the limit in moisture. 

With thick cream, or cream containing a low per cent of 



320 COMPOSITION OF BUTTER 

fat, it is a more difficult problem approximately to control the 
composition of butter. Churning cream at a high temperature 
will invariably result in a high moisture-content and will also 
result in an extreme loss of fat in the buttermilk. 

In churning cream of medium-high fat-content, it is advisable 
to fill the churn only about half full, to churn at such a low tem- 
perature that the butter will gather in about forty-five to fifty 
minutes, and to churn the butter to granules about as large as 
peas. A small variation in the components of butter affects the 
quality very little, provided the butter has been properly made 
and the components properly incorporated. In the same cream- 
ery the composition of butter varies according to the season of 
the year, from day to day or even from churning to churning. 
According to the present methods of manufacturing, water and 
salt are the components most Kkely to vary. Casein will vary very 
little if the butter is efficiently washed and churned in a condi- 
tion in which it will gather firm. Normally, casein is estimated 
at I per cent, occasionally it has been found to run as high as 
4 per cent. It rarely exceeds 2 per cent, and seldom falls as 
low as T^ of I per cent. A high curd-content will show itself in 
the butter in the form of milky brine or in the form of white 
specks. If there is less than 2 per cent present, the brine will 
not be affected. 

One of our large creameries had an average casein con- 
tent of .65 for a year. This was due to their method of washing 
their butter a number of times. An excessive amount of casein 
in butter is supposed to affect its keeping quaHties. 

Curd and milk-sugar are incorporated from the milk into 
the butter during the churning. In the manufacture of butter 
for storage, these substances should be excluded from the butter 
as thoroughly as possible. Milk-sugar and albuminoids consti- 
tute the chief foods for bacterial growth. As deterioration of 
butter has been demonstrated to be due chiefly to the action 
of micro-organisms it becomes essential to restrain their growth 
as much as possible by excluding the food necessary for their 
growth. 

The average salt-content of butter is about 2^ per cent; 



FACTORS THAT AID IN MOISTURE CONTROL 321 

it may vary from i to 4 per cent. The amount of salt properly 
dissolved in butter depends upon the amount of water present. 
The first important step in controlling the salt-content is to have 
a reasonable control of the water-content of the butter. If 
there is 16 per cent of water present in butter it is desirable to 
incorporate as much salt as the water will dissolve within the 
time usually allotted for that purpose. This amount of salt 
suits most of the American butter markets. 

The authors have analyzed commercial butter containing as 
high as 8 per cent salt, the major portion of this being present in 
an undissolved condition. Such butter is called gritty and is 
objected to by the consumer. Salt acts as a preservative to some 
extent and adds flavor to butter provided it is in good condition. 
It has been said that the addition of salt has some effect upon the 
body of butter. 

Richmond asserts that salted butter loses more water on 
standing than unsalted butter. Undoubtedly this is due to the 
fact that the salt added to butter has an affinity for water and 
the drops of water in salted butter are much larger; conse- 
quently, unless the butter is thoroughly worked so as to break 
up the drops of water into smaller drops, this will have a ten- 
dency to cause what is known to the trade as leaky butter. It is 
much more difficult to expel moisture from unsalted butter; 
consequently, a great deal of unsalted butter has been seized by 
the Internal Revenue officials due to the fact that it exceeded 
the prescrited moisture limit set by the Internal Revenue 
Department. 

Unsalted butter, if exposed to medium-high temperatures, 
deteriorates quite rapidly, and frequently has a pronounced 
cheesy flavor. If it is kept at an extremely low temperature it 
keeps well in storage. Creameries have been known to put up 
their butter in an unsalted condition in the summer and put it 
down to zero or below; in the winter they took it out, salted 
it, and worked it up in prints as fresh butter for their winter 
trade. 

Excessive moisture in butter causes it to become dull or 
lusterless in color. Butter that has a very dry appearance and is 



322 COMPOSITION OF BUTTER 

dull in color is invariably high in moisture. Overworking butter 
or working it to a condition where an additional amount of air is 
incorporated not only affects the color but gives the butter, when 
placed in storage, a tendency to deteriorate quite rapidly and 
become fishy. 

The temperature of the wash-water has a bearing upon the 
quality of butter. Water that is too high in temperature has a 
tendency to soften the granules and thus cause them to absorb 
an excessive amount of moisture. When the temperature of 
cream is too high for churning, an excessive amount of butter- 
milk is incorporated in the butter and the latter will not keep well 
either in storage or out of storage. The more butter is worked 
in the presence of water the m.ore water it will take up. 

Making butter from, pasteurized cream has a tendency to 
cause a greater loss of fat in the buttermilk. 



CHAPTER XXI 
DEFECTS FOUND IN BUTTER 

SOME OF THE CAUSES AND THEIR PREVENTION 

In the scoring of butter, 45 points are allowed for flavor, 
25 for body, 15 for color, 10 for salt and 5 for package. This is 
the score that is generally recognized in this country. Some 
expert judges have used the score of 50 for flavor, in which case 
5 are taken off for body, allowing 20 instead of 25. We can, 
therefore, see that flavor is the most important factor in deter- 
mining the quality of butter. The other defects found in butter 
are mechanical defects caused by the process of manufacturing. 
Undesirable flavors affect the selling price of butter more than 
anything else. 

Flat or Insipid Flavor. — Butter that lacks flavor is sometimes 
termed by judges insipid, or flat. Various terms are used in 
describing the flavor of butter. For good butter, such terms 
are used as rich, creamy, aromatic. Butter may be rich in flavor 
without having a pronounced aroma. This kind of butter has 
a pleasant palate flavor. A fiat or insipid taste may be due to 
several causes, such as excessive washing and making butter 
from unripened cream. If cream is pasteurized and a large per 
cent of good starter is used, the fiat flavor, above described, will 
be overcome. 

Butter made from cream of which the flavor is not clean will 
score much higher if it is unsalted. For this reason, many 
creameries manufacture their second-grade cream into butter 
without the use of salt and make what is known to the trade as 
" sweet butter." The theory was advanced some years ago, by 
writers on butter, that heavy salting covered up many defects. 
Various investigations have demonstrated that this is not true. 

323 



324 DEFECTS FOUND IN BUTTER 

Heavy salting has a tendency to bring out the latent flavors. 
Butter made during the winter months is usually deficient in 
.flavor, especially where the cream has not been ripened. Hence, 
flat-flavored butter is more prevalent in winter than during the 
summer months. 

Stable Flavors.^ — Stale and stable flavors are also quite 
prevalent during the winter months. Many of the organisms 
that gain access to milk and cream during the winter months 
come from the stables and are putrefactive organisms that 
decompose the casein, such as Proteus vulgaris, B. suhtilis and 
B. fluorescens. These organisms are usually found in milk 
produced in stables and gain entrance from many sources, 
such as manure, feed, water, dirty utensils and the air; it is 
therefore practically impossible to exclude them. There are 
also a number of other organisms that decompose the casein. 
Keeping milk too long in a poorly ventilated cow-stable has a 
tendency to cause it to take up flavors by absorption. Where 
cows are milked in warm basement stables, poorly ventilated, 
undesirable fermentation is apt to predominate in souring the 
cream without the use of a starter. Two of the principal causes, 
however, of poor quality in cream are failure thoroughly to wash 
and scald all dairy utensils that come in contact with milk or 
cream, especially separators, and failure quickly to cool the 
cream to a low temperature to check fermentation. 

Flavors Acquired by Absorption. — The most common of these 
are house flavors, cellar flavors and vegetable flavors. These 
flavors are all taken up by absorption by the cream. While 
pasteurization will not remove all these flavors, it has the effect 
of removing some of them. Pasteurization to a high tempera- 
ture, i8o° to 185° F. under the flash method, or 170° F. under the 
holding method, and the use of a good starter, will improve the 
flavor of butter made from such cream. House, cellar and food 
flavors are at times so pronounced in butter that a butter judge 
can give a very accurate account of where the cream was kept 
by merely examining the butter. 

Cheesy Flavor. — Cheesy flavor is a defect that is sometimes 
found in butter of low-scoring quality that has been kept for a 



SOME OF THE CAUSES AND THEIR PREVENTION 325 

long time at high temperatures. When butter is deteriorating 
very rapidly in quality it usually reaches the stage where it has a 
pronounced cheesy flavor, which later on changes to what might 
be described as a turpentine flavor. Butter of this character will 
usually sell in the markets as " Seconds." Cheesy flavor is said 
to be due to decomposition of the curdy matter in butter. 

Sour Flavor. — Sour flavor is sometimes caused by over- 
ripening the cream at the creamery. The authors have seen good 
cream from whole milk overripened to such an extent that it 
produced sour-flavored butter. The churning of cream with 
high acidity, without reducing this acidity, wiU produce sour 
butter. Butter judges sometimes describe a sour, disagree- 
able flavor as a dish-rag flavor, because the odor accom- 
panying it is very much like that given off by an unwashed dish 
cloth. The use of unclean cloths for cleansing dairy utensils 
usually means the transmission of undesirable flavors to milk 
and cream. For washing utensils a brush is much preferable to a 
cloth. 

Some creameries that are producing the best butter from 
shipped cream have a set rule that all cream cans must be thor- 
oughly cleansed and sterilized before being returned to patrons. 

Harding and Ayers both report that they were able to produce 
good milk in stables where manure was plentiful, and cobwebs 
were hanging from the ceiling, by sterilizing ah dairy utensils 
that came in contact with the milk or cream. 

Eckles, when connected with the Iowa Experiment Station, 
isolated Bacillus coli aerogenes, added it to pasteurized skim- 
milk and made a starter, and added the same to sweet cream 
for the purpose of ripening or souring it to determine the injurious 
effect it would have upon the flavor of butter. The quality of 
the butter produced was not seriously affected by this starter. 
One of the authors had the privilege of scoring this butter, and, in 
his judgment, it was good commercial butter, though not as 
pronounced in flavor as butter made from cream ripened by a 
culture starter. 

Faulty Factory Conditions. — Bad flavors found in milk, cream 
and butter are sometimes due to conditions prevailing in the 



326 DEFECTS FOUND IN BUTTER 

factories, such as unsanitary pumps and leaky cream vats or 
coils. Unsanitary pumps have been the means of transmitting 
many undesirable flavors to both milk and cream. 

Ayers states that he has investigated the causes of undesirable 
flavors in milk at milk plants, and has found the trouble to be due 
in some cases to unsanitary pumps. An instance of this kind 
came up in one of the best creameries in Iowa, a whole-milk 
plant that had been noted for the excellent quality of the butter 
it was producing. A cut of several cents a pound in the price of 
the butter had been made, due to a very disagreeable flavor that 
it had shown. The maker, who was above the average in intel- 
ligence, was unable to locate the cause of the peculiar flavor that 
was developing in his cream and butter. He asked the State 
Dairy Commissioner to send one of his best men to help them 
locate their trouble. The state inspector examined the creamery 
and found everything in apparently a good condition. He 
weighed the milk himself, and found the quality of the milk 
received was exceptionally good. As soon as the pump was 
started and the milk was pumped up to the heating tank and 
from there passed into the separator, the first cream passing 
from the separator showed the peculiar flavor that was found 
in the butter. From this it was concluded that the trouble was 
in the pump. The pump was taken apart, heated in the furnace 
for some time and thoroughly cleansed, then put together again. 
When the pump and separator were started again, the cream was 
fine. The maker's trouble was that he had not been in the 
habit of taking the pump apart for cleaning but had merely 
pumped water through it and steamed it. The hot steam evi- 
dently condensed, covering up undesirable organisms and pro- 
tecting them from the heat of the steam. From this will be 
seen the importance of sanitary pipes and the use of a pump 
that can be thoroughly cleansed every time it is used, for either 
cream or milk. 

Leaky vats and coils in. creameries are sometimes the cause 
of bad flavors. A leaky vat will produce in cream a pungent, 
disagreeable flavor that is somewhat different from the flavor 
produced by almost anything else, and this will be transmitted 



SOME OF THE CAUSES AND THEIR PREVENTION 327 

to the butter. One of the authors, when scoring educational 
butter, stated in writing to one of the exhibitors that the butter 
had a peculiar flavor that was undoubtedly caused by one of his 
cream vats leaking. Upon examination he found this to be the 
case. 

Feed Flavors. — Some feeds have a pronounced effect upon 
the flavor of cream and butter; some of these are desirable and 
others undesirable. The flavor of turnip tops or turnips affects 
the sale of butter ; but its effect can be largely overcome if these 
are fed after milking. Where cows have access to leeks, wild 
onions or garlic, very undesirable flavors will be produced in 
milk, cream and butter. Garlic and wild onions produce such a 
disagreeable, pungent flavor in butter that some creameries 
have refused to buy cream so flavored, while other creameries 
make a difference of lo cents a pound in the price of the milk-fat. 

Ayers and Johnson, in Farmer's Bulletin No. 6io, give the 
results of their investigation on this subject. 

For the Removal of Garlic or Onion Flavors. — It is a well- 
known fact that heating milk or cream to a high temperature 
will eliminate, in whole or in part, flavors of a volatile nature. If 
we combine with this the aeration of cream, through forcing or 
blowing air into it under pressure, this will further aid in the 
removal of such flavors. 

In Farmer's Bulletin 608 of the U. S. Department of Agri- 
culture is given an outline of an experiment for the removal of 
onion or garlic flavor. In this experiment a vertical, cyHnder- 
shaped, jacketed tank, with an agitator in it, was used for hold- 
ing and heating the milk or cream, and above this was placed a 
smaller tank with a perforated bottom. The milk or cream was 
heated, the temperature being maintained at 145° F. or above. 
Air was then blown into the milk or cream through a pipe 
extending almost to the bottom of the tank; and at the same 
time the milk or cream was constantly pumped into the upper 
tank with the perforated bottom, from which it ran back, in 
fine streams, which reduced the foam on the top of the milk or 
cream in the larger tank. 

It was found in this experiment that the higher the tem- 



328 DEFECTS FOUND IN BUTfER 

perature to which the milk or cream was heated the more efficient 
was the process. While it is impractical to heat milk, for domestic 
use, above 145° F., cream for butter-making can be heated to a 
much higher temperature. Milk or cream with a " strong " 
onion flavor was used. As to results, the onion flavor was 
removed from milk held at a temperature of 145° F. in from 
thirty to sixty minutes; while the flavor was wholly removed from 
cream, held at a temperature of 160° F. in forty minutes. 

A considerable amount of investigational work has been done 
by the Extension Department of the Purdue Station, Indiana, on 
the eradication of wild garlic. We quote from what they have 
to say, as follows: 

" To Eradicate Wild Garlic on a Large Scale. — Break the 
infested land late in the fall, plowing to such a depth as to turn 
up as many of the garhc bulbs as possible. Leave in this con- 
dition through the winter. Replow the field very early in the 
spring — not later than the tenth of April, if possible — disk and 
harrow at least a couple of times and plant to some summer crop 
such as corn, soy beans, cow-peas, potatoes, sorghum or millet. 
No garlic plants or very few will appear during the summer, 
but they will start their growth again in the fall. Remove the 
crop in time to allow another breaking late in the fall. Repeat 
as outlined for the first year, that is, break the field in the fall 
and again early in the spring and plant to summer crop. This 
process continued every season for three to five years will clean 
out the garlic entirely. 

" To Eradicate Wild Garlic on a Small Scale. — Spray the 
plants about the middle of April with orchard heating oil. The 
oil destroys the plants entirely. More garhc may come up, 
however, the following fall or spring from the bulbs which had 
not germinated in the previous season. These must be sprayed 
again. The treatment may have to be repeated, in some cases, 
even in the third year." 

The surest remedy for overcoming these defects in milk and 
cream is to keep the cows in pastures where the said obnoxious 
plants do not grow. Nitrate of potash, common saltpeter, has 
been used quite extensively in cheese sections of the country in 



SOME OF THE CAUSES AND THEIR PREVENTION 329 

the late fall months, when turnip tops or turnips were fed, for 
the purpose of eliminating or removing odors from milk pro- 
duced by cows having access to turnip tops or turnips. 

For butter-making, the German government permits the 
addition of nitrate of potash to milk or cream for the purpose of 
removing flavors produced by the cows eating beets or beet tops. 
Onions and garlic predominate in the early spring and soon dis- 
appear. As soon as the grass advances to such an extent that it 
supplies the wants of the cows, they prefer it to weeds of any kind. 

Advance in Lactation, Winter Feeds and Stable Conditions. — 
It is thought by many that the advanced period of lactation has a 
pronounced detrimental effect on the flavor of butter. Experi- 
ments conducted at the Iowa Experiment Station in 1896 (Bul- 
letin ^^. pages 606-609), by McKay and Eckles, do not sub- 
stantiate this theory. In the various tests made the milk 
from the Experiment Station herd was used. The milk of 
fifteen cows, which averaged an advance of 239 days in their 
lactation period, was classed as stripper milk; while the milk 
of seventeen cows, which averaged an advance of 107 days in 
their lactation period, was classed as milk from fresh cows. 
During this experiment the cows were on good blue grass 
and were being fed, in addition, one-quarter of a pound of 
cottonseed meal at the beginning of the period. The cotton- 
seed meal was gradually increased, until at the end of the experi- 
ment they received i pound each per day. The milking was 
done under personal supervision so that no error might be made 
through mixing the milk from the two lots. After being milked 
and strained into cans the milk was taken directly to the cream- 
ery. When the evening's milk was taken to the creamery it was 
aerated and put in an ice-box which was filled nearly to the top 
of the cans with ice and water. This kept the milk in good con- 
dition until the next morning, when the evening's milk and the 
morning's milk were mixed together and separated. 

The milk from the fresh cows was separated and cared for in 
the same manner as that from the strippers. In order to make a 
closer connection between flavors a starter was prepared from the 
mixed milk of two stripper cows, the periods of lactation of which 



330 DEFECTS FOUND IN BUTTER 

were 339 and 356 days. The skim-milk from the stripper milk 
was permitted to sour and was then used as a starter for souring 
or ripening the cream separated from the stripper milk. The 
fresh cow's milk used for a starter was produced by a cow that 
had been thirty days in lactation. The skim-milk was per- 
mitted to sour in the same way as that from the milk of stripper 
cows. 

Various tests were made of the butter made from the dif- 
ferent milks. This butter was scored by W. S. Moore, who was 
then official scorer for the Elgin Board of Trade, and knew 
nothing of the nature of the experiment. The tubs of butter 
were all scored by number, and received practically the same 
score. The two highest-scoring lots of butter scored 95; one 
of these lots was made from the stripper milk and the other 
from fresh cows' milk. 

From this and similar experiments reported in Bulletin No. 32, 
Iowa Experiment Station, it would seem that the period of lac- 
tation has little or no effect upon the flavor of butter, that is, 
when the milk is separated by centrifugal force, or by the little 
hand separator. Under the gravity system there may be some 
difference, as many dairymen claim there is. A possible explana- 
tion is that the fat-globules, as is well known, are smaller in the 
milk of cows well advanced in lactation, and when cream from 
such milk is raised by the gravity process more time is required 
for the cream to rise than when the milk is from fresh cows 
whose milk contains fat-globules of much greater size. 

A bitter flavor is frequently found in milk or cream that is 
kept for a long time at a low temperature. There seems to be 
present in almost all milk an organism that is able to produce a 
bitter flavor in milk or cream at low temperatures, which are 
unfavorable to the development of the lactic acid organisms. 
Hence, the defects attributed to the period of lactation of the cow 
may be due to the method of separating the cream. 

It is the aim of ahnost all farmers to have their cows come in 
fresh in the spring. Therefore, during the early winter months 
most of the cows are well advanced in their period of lactation. 
At this time they are milked in the stables and fed on dry feed, 



SOME OF THE CAUSES AND THEIR PREVENTION 331 

hence, the opportunity for the milk to become inoculated with 
undesirable organisms is very great. Such conditions are apt 
to create in the minds of some the wrong impression that the 
defects found under winter conditions are caused by the advanced 
stage of lactation. 

Most butter manufactured in the winter has what butter 
judges and dealers term winter flavors. Where the milk is 
received sweet at the creameries and the cream is separated and 
pasteurized and a good starter is used, winter conditions can be 
overcome. The importance of pasteurization and the use of a 
good starter during the winter months cannot be emphasized 
too strongly. 

A quotation from Bulletin loi, Iowa Experiment Station, 
page 167, will help to show the improvement that can be made 
in the flavor of butter under right methods. " During the spe- 
cial winter course, beginning the latter part of December, 1907, 
and continuing until January, 1908, the Dairy Department of 
the Iowa Experiment Station arranged with the Randall Cream- 
ery Company, Randall, Iowa, to purchase their cream to be used 
during the special short-course." In this case it is presumed that 
the cows were well advanced in the period of lactation, they were 
certainly subject to normal winter conditions. The Randall 
Creamery, which is a whole-milk creamery, received the milk 
and separated it. The sweet cream, in this case, was shipped to 
the Iowa Experiment Station where it was pasteurized, ripened 
by the use of a good starter and churned the next morning. The 
cream skimmed at the plant contained 42 to 45 per cent butter-fat, 
after the starter was added it contained 32 to 7,^ per cent fat. 
As the Randall Creamery Company were shipping their butter 
to Gude Bros., New York, they made a request that the butter 
produced from their cream at the Iowa Experiment Station be 
shipped to the same place. This was done, with instructions 
to the Gude Bros, and P. H. Keiffer, the well-known butter judge 
of that firm, to score each shipment critically and report on the 
same. At the close of the shipments, Mr. Keiffer made the 
following report: 

" I am very much pleased to be able to report that the butter 



332 DEFECTS FOUND IN BUTTER 

which you shipped us this winter, made from cream obtained 
from the Randall Creamery during the ' Short Course,' was very 
fancy, and scored from 93 to 96 points. Very Httle butter 
arrived at that time as fine in flavor as this. Our best trade was 
well pleased with your butter. I wish that more of the cream- 
eries were making this high quahty butter at the time of year 
when it is so difficult to make it. The workmanship was perfect 
in every respect, so far as I could see, and the flavor was fine." 

If the above-mentioned cream had been permitted to sour 
naturally the chances are that the flavor would have been very 
inferior instead of fine. The authors have found the best tem- 
perature for ripening cream during the winter months to be 70° 
to 74° F. 

From the above it seems that the flavor of the butter is not 
injured by the advance in the lactation period of the cow but 
rather by undesirable fermentations that develop in the cream if 
permitted to sour naturally, especially during the winter months. 

Tallowy Flavor. — Tallowy flavor is sometimes found in butter, 
usually in butter that has been kept under rather unfavorable 
conditions. Butter of this character has a taste somewhat 
similar to that of old tallow. This peculiar flavor is more apt to 
develop in print than in tub butter. It occurs, however, in tub 
butter when it has been bored a number of times, thus bringing 
the air into contact with the inner parts of it. It is found some- 
times in print butter which has been exposed to the air and 
light, and the color may be seriously affected, even to the extent 
of bleaching the surface butter white. 

The cause of tallowy flavor in butter is oxidation. U. S. 
Bulletin 84 shows the effect of air on the quality of butter. A 
number of cans of butter were put up by Gray, and hermetically 
sealed. Some of these cans were packed full, some about three- 
quarters full, some about half full, and the butter in one lot was 
put in loosely where the air came into contact with it. Thus, 
the amount of butter in these cans was so varied that different- 
sized air spaces were left. The solidly packed butter in every 
instance kept the best in storage. The butter that was loosely 
packed deteriorated very rapidly, showing a tallowy or fishy 



SOME OF THE CAUSES AND THEIR PREVENTION 333 

flavor. Mr. Gray, in commenting upon this butter, makes the 
following statement: 

" Comparing the average scores of butter in full cans and in 
partially full cans it will be noted that there were differences of 
I to 5 points in favor of the full cans. It does not seem necessary 
to take up these differences in detail. This deterioration was 
without doubt due to air in the partially full cans. Since in 
packing butter in cans there is no necessity for having the cans 
only partially full, neither is this economical, the writer does not 
hesitate to state that where the sealing is done at atmospheric 
pressure the cans should be entirely filled, leaving as little air 
space as possible. This principle may be applied to packing 
butter in other packages. The butter should be packed solidly, 
leaving as few air spaces as possible. Air having a deteriorating 
effect on the keeping of storage butter, it would be expected that 
butter stored in small open packages, as pound prints, would 
not keep so well as butter in large packages. This is a beHef 
that has already been accepted by many." 

High-scoring butter that has been bored a number of times at 
conventions or butter contests, has a tendency to deteriorate in 
quahty and show a slight tallowy flavor. One of the authors 
has had the opportunity of judging butter at various times in 
almost every dairy state in this country, and in some of the foreign 
countries, thus being afforded a wide range of opportunity for 
examining prize-winning tubs or packages of butter. 

The impression prevails with some that high-scoring butter 
lacks keeping quahty. The only way whereby this statement 
could be verified would be to place a tub of the same butter in 
storage and leave it there at storage temperature for six or seven 
months. When we take into consideration that some of the 
best butter at a contest is bored a great many times and thus 
exposed to the air. it would be difiicult to determine whether the 
defect in the butter were caused by high ripening or by excessive 
boring. An instance of excessive boring was brought to the 
attention of the authors in a national contest that was held at 
Milwaukee some years ago, where both authors were present 
acting in the capacity of experts, one pointing out the delects in 



334 DEFECTS FOUiVD IN BUTTER 

the butter and the other writing each exhibitor giving suggestions 
as to the possible cause of the defects existing. Three well- 
known judges worked in this contest, one from Philadelphia, 
one from Boston and the third from Chicago. There were 
between seven and eight hundred entries of butter exhibited. 
On the first day's scoring the judges set aside a tub of extra 
fine butter to be rescored. The butter had a fine aroma and a 
clean palate flavor. It had what the authors would describe as a 
creamy, pleasant flavor. The quality of this butter was such 
that it was used as a standard by which to gage the score of the 
other tubs of butter in the final scoring. It is the custom in a 
large contest of this kind for the judges to set aside all butter 
that will score as high as 95 points out of a possible 100. This 
butter is placed in what the judges term the " shake-down." 
After all the other butter is scored, the judges after resting for 
some time go to work on the " shake-down " with a view to 
placing the highest scores. This particular tub of butter was 
used as a standard by which to fix the other grades. The result 
was that this butter was bored possibly twenty-five or thirty 
times. When the judges in the final score placed this tub fourth, 
on the ground that it was showing at that time a slight tallowy 
flavor, their decision caused some dissension and dissatisfaction. 
It certainly was not fair to this exhibitor to have his butter bored 
so many times, and the authors believe that the repeated boring 
of a tub of butter in a contest with the resulting contact with the 
air is not a fair test of its keeping qualities. 

The bleaching of tallowy butter does not usually occur until 
it has been held for some time. Tallowy flavor is not very 
frequently found in butter that has been placed in cold storage. 

Overworking butter to the extent that it will become greasy 
in appearance and taste has a tendency to cause tallowy flavor. 
By overworking butter, extra air is incorporated. Butter that is 
churned in such condition that the granules will gather firm 
will stand an extra amount of working without any effect upon 
the body. If cream is churned immediately after reaching churn- 
ing temperature, before the fat has sufficient time to be thor- 
oughly chilled, the fat has a tendency to gather in a soft condi- 



SOME OF THE CAUSES AND THEIR PREVENTION 335 

tion, and if such butter is worked to the extent of avoiding mot- 
tles and thoroughly incorporating the salt, there is danger 
of the body being seriously affected and the butter having a 
greasy or lardy taste. 

Butter which has been well made and kept away from the light 
when placed in storage will seldom, if ever, show a tallowy flavor. 

Metallic Flavors. — A heavy loss is sustained by the butter 
industry every year through metallic and fishy flavors. There 
does not seem to be a clear understanding between some butter 
judges as to the distinction between these two classes of flavors. 
Metallic flavor and fishy flavor are two entirely different things. 

Metallic flavor shows in the butter as soon as it is churned 
and is invariably found in butter made from extremely sour 
cream, while fishy flavor develops in butter on standing. What 
actually causes metallic flavor is not thoroughly understood, and 
various causes have been assigned by different people. Metallic 
butter has a pungent flavor, characteristic of the taste of metallic 
salts. Many people are of the opinion that cream acquires a 
metallic flavor by being shipped in rusty cans or coming in 
contact with vats or coils from which a portion of the tin has 
been removed. 

Certain creameries have reported that in some cases the first 
churning from a vat of cream is free from metallic flavor, while 
this flavor is present in the second churning from the same vat. 
This would seem to indicate that the flavor is due to the develop- 
ment of some undesirable fermentation, or to bacterial action. 

The peculiar feature about metallic flavor is that it is a sea- 
sonal condition; it comes and disappears. Heat seems to inten- 
sify it or make it more pronounced. The authors have known 
creameries that were troubled with metallic flavor which dis- 
appeared when they discontinued pasteurization. Cream coming 
in contact with vats, coils or cans from which the tin has been 
removed may develop a metallic flavor as a result of this. How- 
ever, when we take into consideration that metallic flavor is a 
seasonal condition, the theory of rusty cans or the partial 
removal of tin from vats or coils does not offer a complete explan- 
ation, as creamerymen use the same cans and vats during the 



336 DEFECTS FOUND IN BUTTER 

entire season. If the trouble were wholly due to the removal of 
the tin from the vats or coils, it would continue throughout the 
year. 

Guthrie reports that he placed 157 samples of cream in sterile 
glass bottles and inoculated with an individual species of bacteria, 
and that 52 showed metallic flavor. Naturally the creamery- 
men will be more interested in what will prevent metallic flavor 
than what causes it. 

One of the largest creamery companies in this country 
which, like others, was formerly troubled with metallic flavor 
claims it has not had any difhculty for several years, due to the 
method observed in manufacturing. The president of the com- 
pany stated to one of the authors that they had bid good-bye 
to metallic flavor several years ago. The method they pursue 
is neutralization to a low degree of acidity and thorough cleanli- 
ness. If metallic flavor makes its appearance they reduce the 
acidity to .27 per cent before pasteurization and then again, by 
adding limewater, reduce the acidity to .04 or .05 per cent, and 
ripen with a pure culture. In addition to this, they thoroughly 
cleanse all pipes and faucets, and everything else with which the 
cream comes in contact. They maintain that this method of 
procedure has entirely eliminated metallic flavor from the 
butter they manufacture. 

Fishy Flavor. — Fishy flavor causes greater losses in butter 
than any other one defect. In recent years a great many so- 
called discoveries have been made by different scientists as to the 
actual cause of fishy flavor. These discoveries have been inves- 
tigated and disputed by other scientists, and the result is that 
fishy flavor is still with us. Butter made from high-acid cream 
will invariably go fishy if placed in cold storage for a long time, or 
for the natural storage period. 

Prior to the introduction of partial neutralization of acidity 
in cream, butter made from hand-separator cream containing a 
high per cent of acid invariably turned fishy when kept in storage 
for any length of time. One of the leading dealers in Chicago 
stated that for two years he had bought butter made by some of 
the large creameries from sour cream the acidity of which had 



SOME OF THE CAUSES AND THEIR PREVENTION 337 

not been reduced, and that in almost every case the butter was 
fishy when it came out of storage. He said that as a result of 
this he had made up his mind never to buy any butter from the 
so-called centralized creameries. The same firm now prefers to 
buy butter for storage purposes from large creameries where the 
acidity of the cream is reduced or controlled. 

The following is a quotation from U. S. Bulletin by L. A. 
Rogers, S. C. Thompson and J. R. Keithley, page 8 : 

" In a tabulation of the examination of 259 samples of 
experimental butter from cream of known acidity, of 137 sam- 
ples from cream having an acidity below 0.3 per cent, only 2, or 
1.5 per cent, were marked ' fishy,' while of 122 samples having 
an acidity of 0.3 per cent or over, 60, or 49.2 per cent, were fishy. 
However, in all results which are dependent on the sense of 
taste, allowance should be made for difference of opinion and in 
the conception of the flavor associated with any particular 
designation." 

U. S. Department of Agriculture Bulletin 84, page 23, 1906, 
by C. E. Gray and G. L. McKay, entitled " The Keeping Qual- 
ities of Butter made under Different Conditions and Stored at 
Different Temperatures," would indicate that acid has a pro- 
nounced effect in producing fishy flavor in butter unless the 
acidity of the cream has been reduced by partial neutralization. 
In this investigation part of the butter was made at Topeka, 
Kansas', from sour cream. Other lots were made at Monticello, 
Iowa, from sweet or whole-milk cream. The butter made from 
sweet cream did not turn fishy in storage, while practically all 
the butter made from sour cream had a pronounced fishy flavor 
after being kept in storage for some time. 

Fishy flavor may be prevented with certainty by making 
butter from pasteurized sweet, cream. Butter made from pas- 
teurized sweet cream with a starter added, but without ripening, 
seldom if ever becomes fishy. 

Of 25 different churnings of cream made at Strawberry Point, 
Iowa, July, 1907 (Bulletin loi, by McKay and Bower, page 164), 
8 were made from unpasteurized cream and 17 from pasteurized 
cream. The cream was ripened in all cases with a pure culture 



338 DEFECTS FOUND IN BUTTER 

starter, average acidity developed .68 per cent. A tub of butter 
from each churning was stored in New York between six and 
seven months, and came out of storage without any trace of a 
fishy flavor. The butter was scored when entering storage and 
when coming out by P. H. Keiffer, the well-known butter judge. 
The average scores on flavor were, first scoring 38.17, second 
scoring 38.25. The butter was pronounced by the expert 
scorer as being some of the finest butter he had ever seen come 
out of storage. Two 56-pound boxes from each churning were 
shipped to London, Liverpool, and Manchester, England, where 
they were scored by experts and pronounced unusually fine. 
The average in England, on flavor, was 38.5. The Strawberry 
Point Creamery at that time received about 50,000 pounds of 
milk daily. The milk was all inspected before being taken into 
the creamery, and any milk that was sour or tainted was rejected. 
The milk was all separated by power separators and the cream 
skimmed so as to contain a high per cent of milk-fat. The high 
per cent of acid developed in this case apparently had no effect 
upon the keeping quality and did not produce a fishy flavor. 
It would, therefore, seem that the quality of the milk or cream 
used in the manufacture of butter is somewhat responsible for 
its going fishy. 

The Danish butter, which has gained a world-wide reputa- 
tion, is practically all made from whole milk dehvered at the 
factories, the cream being ripened with a culture starter. While 
cream of high acid has a tendency to go fishy, fishiness cannot 
be attributed entirely to the development of acid in cream. At 
the present time probably 90 per cent of the butter produced in 
this country is produced from cream separated on the farms. 
The washing of the separators and other dairy utensils is entirely 
in the hands of the producer. It is only reasonable to suppose 
that some of the patrons of almost every creamery do not pursue 
sanitary methods in the care of their separators and other utensils 
that come in contact with the cream. Such cream is undoubt- 
edly inoculated with undesirable organisms before it reaches the 
creamery, and if an attempt is made to ripen or develop much 
acid in it, other changes will also take place. To make butter 



SOME OF THE CAUSES AND THEIR PREVENTION 339 

possessing good keeping qualities, under present conditions, it is 
necessary to neutralize when the cream is very sour, and develop 
a low degree of acidity. The Dairy Division has found that 
pasteurizing cream with a low degree of acidity and churning it 
sweet, or without the use of a starter, produces a butter that is 
entirely free from fishy flavor. 



CHAPTER XXII 
JUDGING AND GRADING BUTTER 

Butter may be judged from a commiercial and from an indi- 
vidual standpoint. Individual judgments of the same butter 
may vary considerably. It is important that the judge should 
become familiar with the quality of butter as required by our 
standard markets, and then judge the butter according to the 
demands of the mass of the consumers, rather than according 
to personal likes and dislikes. In order to become a good butter- 
judge, it is essential that the senses of taste and smell be acute. 
Even if one's taste and smell are keen and sensitive, consider- 
able practice or experience is necessary. Almost any one can 
tell a good sample of butter from a very poor one, but when it 
comes to differentiating between two samples which are nearly 
alike in quaHty, skill and experience are required. 

The chief requirement in scoring butter is to become thor- 
oughly familiar with the ideal flavor of butter; then by repeated 
comparisons of different samples of butter with this ideal 
flavor, one will soon become efficient in grading the butter. 

Standard for judging. — In America the distinct qualities 
which are noticed in butter are designated according to the 
basis of points given below. It will be noticed that different 
values are given to the different characteristics, according to their 
relative importance. The score-card given below is used com- 
mercially, and is based upon loo as the perfect score: 

Score Card 

No Perfect Score Remarks 

FIa^ or 45 

Body.. 25 

Color 15 

Salt 10 

Style 5 

Total 100 

Date Scored by 

340 



MANNER OF JUDGING 341 



MANNER OF JUDGING 



Body. — After the trierful of butter has been drawn out, the 
first thing to notice is the aroma, and the body or texture of the 
butter. The butter on the outside should be examined at once 
before it is affected by the temperature of the room. Notice its 
color, whether it is even or uneven, low or high. Determine by 
the appearance of the butter and the way it feels to the palate 
whether it is greasy, tallowy, spongy, or sticky. The amount 
and condition of brine should also be noted. These character- 
istics and their causes have been previously discussed. Stroke 
the plug of butter with a knife to observe the color closer. Squeeze 
it with the thumb to ascertain the character of the body. The 
aroma of the butter should also be noticed in connection with 
scoring the butter on body or texture, as it is more pro- 
nounced immediately after the trierful of butter has been 
drawn. 

Flavor. — It is impossible to describe all the different flavors 
found in butter. There are perhaps as many distinct butter 
flavors as there are shades of color. However, there are a few 
flavors which stand out more prominently and are more commonly 
met with than any of the others. Good butter should possess a 
clean, mild, rich, creamy flavor, and should have a delicate, mild, 
pleasant aroma. Some butter- judges, especially foreign judges, 
allow a separate number of points for aroma of butter in the score- 
card. This has been suggested in the United States also, owing 
to the fact that butter may have httle aroma and still have a good 
flavor. 

Color. — The color should be bright and even. When a plug 
of butter is drawn with a trier and is held up to the Hght, it 
should not be cloudy and dense, but should be almost trans- 
parent and bright. The chief fault found with the color of 
butter is unevenness. It may be streaky or mottled, or it may 
be too high or too low. The shade of color will vary according 40--- 
the different markets; in most of our markets a straw color is 
preferred. There has been a tendency recently to recommend a 
comparatively light shade of color in butter. A reddish color 



342 JUDGING AND GRADING OF BUTTER 

should be guarded against, except when the market demands 
it. If too much color is added, butter will assume this hue, 
which is undesirable. 

Salt. — The amount of salt likewise depends upon the market, 
and unless the salt-content is extremely high, or extremely low, 
butter should not be criticized on account of the amount of salt. 
The chief thing to consider in judging butter on its salt-content 
is the condition of the salt. Notice whether it has been thor- 
oughly dissolved and evenly distributed. 

Style. — The style is the appearance of the butter and package. 
Whatever the shape of the package, the chief thing to consider 
is whether it is clean and neatly finished. 

CLASSIFICATION— GRADES AND SCORES 

While the different butter markets differ more or less as to 
details, in their classification and grading of butter, they corre- 
spond closely when it comes to the large essentials. As the New 
York and Chicago markets are the two great butter markets of 
the United States, the following is quoted from the Rules of the 
New York and Chicago Mercantile Exchanges, respectively: 

New York 

1. Butter shall be classified as Creamery, Renovated, Ladles, 
Packing Stock and Grease Butter. 

DEFINITIONS 

2. Creamery. — Butter offered under this classification shall 
have been made in a creamery from cream separated at the 
creamery or gathered from farmers. 

3. Renovated. — Butter offered under this classification shall 
be such as is made by melting butter, clarifying the fat therefrom 
and rechurning the same with fresh milk, cream or skim-milk, or 
other similar process. 

4. Ladles. — Butter offered under this classification shall be 
such as is collected in rolls, lumps, or in whole packages and 
reworked by the dealer or shipper. 



CLASSIFICATION— GRADES AND SCORES 343 

5. Packing Stock. — Butter offered under this classification 
shall be original farm-made butter in rolls, lumps or otherwise, 
without additional moisture or salt. 

6. Grease butter shall comprise all classes of butter grading 
below thirds, or of packing stock grading below No. 3 as herein- 
after specified free from adulteration. 



7. Creamery, renovated and ladles shall be graded as extras, 
firsts, seconds and thirds; and packing stock shall be graded as 
No. I, No. 2 and No. 3. 

DEFINITION OF GRADES 

8. Grades of salted butter must conform to the following 
requirements : 

Extras 

9. Shall be a standard grade of average fancy quality in the 
season when offered under the various classifications. Ninety 
per cent shall conform to the following standard; the balance 
shall not grade below firsts: 

Flavor. — Must be sweet, fresh and clean for the season when 
offered if creamery, or sweet, fresh and reasonably clean if ren- 
ovated or ladles. 

Body. — Must be firm and uniform. 

Color. — Not higher than natural grass, nor lighter than light 
straw, but should not be streaked or mottled. 

5a/^.— Medium salted. 

Package. — Sound, good, uniform and clean. 

Firsts 

10. Shall be a grade next below extras and must be good butter 
for the season when made and offered, under the various classi- 
fications. Ninety per cent shall conform to the following stand- 
ard; the balance shall not grade below seconds. 

Flavor. — Must be reasonably sweet, reasonably clean and 
fresh if creamery or renovated, and reasonably sweet if ladles. 
Body. — Must be firm and fairly uniform. 



344 JUDGING AND GRADING OF BUTTER 

Color. — Reasonably uniform, neither very high nor very hght. 
Salt. — May be reasonably high, light or medium. 
Package. — Sound, good, uniform and clean. 

Secoiids 

1 1 . Shall be a grade next below Firsts. 
Flavor. — Must be reasonably good. 

Body. — If Creamery, must be solid boring. If Ladles or 
Renovated, must be 90 per cent solid boring. 
Color. — Fairly uniform, but may be mottled. 
Salt. — May be high, medium or light. 
Package. — Good and uniform. 

Thirds 

12. Shall be a grade below Seconds and may consist of pro- 
miscuous lots. 

Flavor. — May be off-flavored and strong on tops and sides. 

Body. — Not required to draw a full trier. 

Color. — May be irregular or mottled. 

Salt. — High, light or irregular. 

Package. — Any kind of package mentioned at time of sale. 

13. (For grades higher than Extras, see paragraph No. 28). 

No. I Packing Stock 

14. Shall be sweet and sound, packed in large, new or good 
uniform second-hand barrels, having a wooden head in each end, 
or in new tubs, either to be parchment paper lined. Barrels and 
tubs to be packed full. 

No. 2 Packing Stock 

15. Shall be reasonably sweet and sound, and may be packed 
in promiscuous or different kinds of barrels, tubs or tierces, with- 
out being parchment paper lined, and may be packed in either 
two-headed or cloth-covered barrels. 

No. 3 Packing Stock 

16. Shall be a grade below No. 2, and may be off-flavored, or 
strong; may be packed in any kind or kinds of packages. 



CLASSIFICATION— GRADES AND SCORES 345 

17. Charges for inspection of Packing Stock shall be the same 
as the rules call for on other grades. 

18. Mold. — There shall be no grade for butter that shows 
mold. 

Scoring 

19. Scoring. — The standard official score shall be as follows 
and shall apply to Salted Creamery Butter only: 

Points 

Flavor 45 

Body . . : 25 

Color 15 

Salt 10 

Style.... 5 

100 

20. Extra Creamery may score either 91, 92 or 93 points at 
the discretion of the Butter Committee, who shall determine the 
required score from time to time in such manner that it shall 
represent an average fancy quality in the season when offered. 
But butter scoring more than required for Extras shall be deliv- 
erable on a contract for Extras, and may be branded as such at the 
request of seller, or buyer. Any change in the Standard score 
required for Extras shall, after authorization by the Butter Com- 
mittee, be announced by the caller at the opening of the next 
regular call and posted upon the bulletin board of the Exchange 
and be effective twenty-four hours later. 

21. The minimum score of Firsts shall, at all times, be 4 
points below the score required for Extras. 

22. The minimum score of Seconds shall be 5 points below 
the minimum score required for Firsts. 

23. The minimum score of Thirds shall be 7 points below the 
minimum score required for Seconds. 

UNSALTED CREAMERY 

Exiras 

24. Shall be a standard grade of average fancy quality in the 
season when offered under the various classifications. Ninety 



346 JUDGING AND GRADING OF BUTTER 

per cent shall conform to the following standard; the balance 
shall not grade below Firsts. 

Flavor. — Must be sweet, fresh and clean for the season when 
offered. 

Body. — Must be firm and uniform. 

Color. — May be very light straw, white, or natural grass, but 
must not be streaked or mottled. The seller must specify the 
color at time of sale. 

Package. — New, uniform and clean. 

Firsts 

25. Shall be a grade next below Extras and must be good 
butter for the season when made and offered, under the various 
classifications. Ninety per cent shall conform to the following 
standard; the balance shall not grade below Seconds. 

Flavor. — Must be reasonably sweet, reasonably clean and 
fresh. 

Body. — Must be firm and fairly uniform. 

Color. — May be very light straw, white, or natural grass, but 
must not be streaked or mottled. The seller must specify the 
color at time of sale. 

Package. — Sound, good, uniform and clean. 

Seconds 

26. Shall be a grade next below Firsts. 
Flavor. — Must be reasonably good. 
Body. — Must be soHd boring. 

Color.- — Fairly uniform, but may be mottled. 
Package. — Good and uniform. 

Thirds 

27. Shall be a grade below Seconds and may consist of 
promiscuous lots. 

Flavor. — May be off-flavored and strong on tops and sides. 

Body. — Not required to draw a full trier. 

Color. — May be irregular or mottled. 

Package. — Any kind of package mentioned at time of sale. 



CLASSIFICATION— GRADES AND SCORES 347 

Scoring 

Points 

Flavor 45 

Body 25 

Color 20 

Style 10 

100 

SALES UNDER THE CALL 

28. Creamery butter salted of a score higher than required 
for Extras may be offered and bid for by score. The score of 
such butter may be considered its grade; or such higher scoring 
butter may be delivered on a contract for Extras. This grade 
of butter, above " Extras," is commonly designated by the trade 
as " Specials." 

Chicago 

1. Butter shall be classified as Creamery, Centralized Cream- 
ery, Held Butter, Renovated, Ladles, Packing Stock and Grease 
Butter. 

DEFINITIONS 

2. Creamery. — Butter offered under this classification must 
be made in a creamery, the cream having either been separated 
from the whole milk at the creamery or received by team or 
motor at the creamery direct from the farm. 

3. Centralized Creamery. — Butter offered under this classi- 
fication must be made in a creamery. The cream used in the 
manufacture of this butter may be gathered direct from the 
farmer or shipped in from individual shippers or cream stations. 

4. Held Butter. — Butter offered under this classification 
shall be butter that has become cold storage butter by virtue 
of the laws of the United States or of the state in which such 
butter is sold. 

5. Renovated. — Butter offered under this classification shall 
be such as is made by melting the butter, clarifying the fat 
therefrom and rechurning the same with fresh milk, cream, skim- 
milk or other similar processes. 



348 JUDGING AND GRADING OF BUTTER 

6. Ladles. — Butter offered under this classification shall be 
such as is collected in rolls, lumps or whole packages and reworked 
or rechurned, resalted or recolored by the dealer or shipper. 

7. Packing Stock. — Butter offered under this classification 
shall be original butter without additional moisture or salt from 
creamery or dairy (but may be from miscellaneous sources), 
which has been collected in any quantity and packed in tubs, 
barrels or other containers. It must be of a quality fit for 
human consumption as food and free from adulteration. 

8. Grease Butter. — Butter offered under this classification 
shall consist of all grades of butter below thirds. If packing stock, 
below No. 3, and free from adulteration. 

GRADES 

9. Creamery and Held Creamery shall be graded Extras, 
Firsts, Seconds and Thirds. Centralized Creamery shall be 
graded Extras, Standards, Firsts, Seconds and Thirds. Reno- 
vated and Ladles as Firsts and Seconds. Packing Stock as 

No. I, No. 2, and No. 3. 

Scoring 

10. The standard official score for salted butter shall be as 
follows: 

Points 

Flavor ' . 45 

Body 25 

Color 15 

Salt 10 

Style 5 

11. The standard official score for unsalted creamery butter 
shall be as follows : 

Points 

Flavor 45 

Body 30 

Color 15 

Style 10 

12. All grades of butter must conform to the following require- 
ments : 



CLASSIFICATION— GRADES AND SCORES 349 

Extras 

13. Shall consist of the best grade of butter in the season when 
produced and must score 92 points or better. 

Flavor must be sweet, fresh and clean when offered as fresh, 
and sweet and clean when offered as Held Creamery. Body 
must be firm and of good texture. Color may be either light 
straw color, medium or high, but must be uniform and neither 
streaked nor mottled. Salt may be defined as light, medium or 
high, but must not be gritty. Package, new, sound, good, uni- 
form and clean. 

Standards 

14. Standards shall be a grade of centralized creamery of 
average fine quality in the season when offered, scoring 90 points 
and above. Flavor must be fresh and clean if fresh, and clean 
if held. Body must be firm and of good texture. Color may be 
either light straw color, medium or high, but must be uniform, 
neither streaked nor mottled. Salt may be defined as light 
medium or high, but must not be gritty. Package, new, sound, 
good, uniform and clean. 

Firsts 

15. Shall be a grade just below Extras, scoring from ^^ to 
(but not including) 92 points, must be good butter for the season 
when made and offered under this classification. 

Flavor must be reasonably clean and fresh if Creamery, 
Centralized Creamery or Renovated, and reasonably clean and 
reasonably sweet if Held. Body must be firm and of fairly good 
texture. Color reasonably uniform, neither very high nor very 
light. Salt may be light medium or high. Package, new, sound, 
good, uniform and clean. If Ladles, must be 90 per cent solid 
boring, color reasonably uniform, package sound and clean. 

Seconds • 

16. Shall be a grade below Firsts. The minimum scoring of 
Creamery Seconds shall be 4 points below the minimum scoring 
required for Firsts or a range of from 84 to (but not including) 88. 

Flavor must be fairly good. Body, if Creamery, Centralized 



350 JUDGING AND GRADING OF BUTTER 

Creamery or Held, must be solid boring. If Renovated or Ladles, 
must be 90 per cent solid boring. Color, fairly uniform, but 
may be mottled. Salt may be light medium or high. Package, 
good and uniform. 

Thirds 

17. Shall be a grade below Seconds and may consist of pro- 
miscuous lots. The minimum scoring for Creamery Thirds shall 
be 5 points below the minimum scoring for Seconds, or a range 
from 79 to (but not including) 84 points. 

Flavor may be off-flavored and strong on tops and sides, more 
or less rancid. Body not required to draw a full trier. Color 
may be irregular or mottled. Salt high, light or irregular. 
Package, any kind of package mentioned at deHvery. 

No. I Packing Stock 

18. Shall be original butter, solid boring, sweet and sound, 
without additional moisture or salt, free from mold, normal in oil 
contents, packed in barrels or in tubs or boxes. Where in bar- 
rels, parchment-lined packages are preferred. When in either 
tubs, boxes or barrels, same should be packed full. 

No. 2 Packing Stock 

19. Shall be original butter, 85 per cent of it solid boring, the 
other 1 5 per cent fairly soKd boring, reasonably sweet and sound 
for the grade offered; may be slightly deficient in oil contents, 
must be free from mold and may be packed in different kinds of 
barrels, tierces, pails or boxes with or without paper Hning. 

No. 3 Packing Stock 

20. Shall be a grade of quaHty just below No. 2 Packing 
Stock, but above the classification of Grease Butter; may be 
packed in any or all kinds of packages. 

EXPORT BUTTER 

The observations of the authors have been that the reputation 
of the American butter on the English market is not all that is 
desirable. Some American butter is good enough to sell on an 



EXPORT BUTTER 



351 



equality with Danish butter, and in some instances it is palmed 
off as such. Much poor butter, however, has been allowed to 
go to the EngHsh market, and this has in some measure ruined 
the reputation of our butter. 

Butter for export purposes should be of the very best, and 
made in such a way as to insure good keeping qualities. 




Fig. 128. — Shipping Russian Butter from Siberia. (U. S. Govt. Bui.) 

The standing of the different kinds of butter, as observed 
on the English market, were as follows : 
(i) Fresh French Rolls. 

(2) Danish Creamery. 

(3) Irish Creamery. 

(4) New Zealand. 

(5) Canadian, Australian, Argentine, United States, and 
Siberia. 



(i) Danish. 

(2) New Zealand. 

(3) Siberia. 



For Storage Purposes 



CHAPTER XXIII 
COLD STORAGE AND BUTTER FOR STORAGE PURPOSES 

History of Cold Storage. — From early pioneer days the people 
had a knowledge of the fact that by placing perishable food 
products where the temperature was low they could keep them 
much better. Many of the early settlers discovered that there 
was a zone about 6 to lo feet below the surface of the ground 
where the temperature was low. Hence they dug holes in the 
ground in which to keep various kinds of food products. Later, 
ice was used in various ways to lower the temperature. It was 
discovered that the lower the temperature, the better the food 
products would hold their flavor. 

Refrigeration, as we have it to-day, is the result of a gradual 
evolution as to both process and efficiency. Cooling by means 
of ice was practiced by the ancients. We read that the monarch, 
Nero, had ice-houses built in Rome for the storing of natural ice. 
The cooling effect obtained through dissolving certain salts was 
recognized and made use of, as far back as 1762, by. Fahrenheit, 
the inventor of the thermometer that bears his name. Salt- 
and-ice mixtures have been used for many years for refrigerating 
purposes, including the making of ice-cream, etc. In what is 
known as the " Cooper System " of refrigeration, ice and calcium 
chloride are used. Under this system the temperature of a well- 
constructed refrigerator can be maintained at 20° F., or below. 

About 1845, ^r. Gorrie of New Orleans invented a cold-air 
refrigerating machine. Under his system the air is compressed 
but is not condensed to a liquid; hence it is not so practical as 
the more modern systems. At one time it was used extensively 
on ships on account of the absence of obnoxious gases. This 
system, while mechanical, differs from those here classed under 
that head. 

352 



MECHANICAL REFRIGERATION 353 

Mechanical Refrigeration. — The underlying principle of 
mechanical refrigeration, that of the consumption of heat in the 
vaporization of a liquid, is not a new one. In the hot climates of 
many eastern countries, water for drinking purposes is kept in 
porous earthen vessels so that the wind may evaporate the 
moisture as it oozes through the pores of the vessel and so cool 
the water. In Arizona, and to some extent in Oklahoma, the 
farmers cool their cream by wrapping the cream can with a 
suitable cloth which acts as a wick to carry up moisture to be 
evaporated and, in so doing, absorbs heat from the cream in 
the can or, in other words, cools the cream. 

A more refined and very much more effective application of 
this principle of cooling, through the vaporization of a liquid, 
is made under the modern system of mechanical refrigeration. 
Under the Compression system, which is explained in the chap- 
ter entitled, " Coohng Facihties for Creameries " the two sub- 
stances most commonly used are anhydrous ammonia and car- 
bonic acid gas. Professor Carl Linde of Munich invented the first 
ammonia compression machine in 1873. The carbonic acid 
machine, also compression, and copied after Linde's designs, 
appeared in 1880. In large creameries and central cold storage 
houses in this country, ammonia plants are much more common 
than carbonic acid plants, although on ships the latter are prob- 
ably in more general use. In another system of mechanical 
refrigeration, what is known as the Absorption process is used. 
Under this system two substances are used, one of which remains 
a Hquid and absorbs the other at ordinary temperatures. One 
combination is that of sulphuric acid and water, and another, 
water and ammonia. 

Benefits of Cold Storage. — Mechanical refrigeration was first 
introduced into the United States about 1888. Its general effect, 
however, upon the storing of food and upon the market was not 
appreciably felt until about 1902. Cold storage is of great bene- 
fit to the pubHc as a whole. As to the consuming public, it 
enables them to get perishable food products held over in many 
cases from the time of high production to the time of scarcity, 
thus establishing a greater uniformity of price throughout the 



3.54 COLD STORAGE AND BUTTER FOR STORACxE PURPOSES 

year. The producer of perishable products is also benefited 
from the fact that he gets higher prices during the time that he 
has his largest supply, which he would not be able to get if such 
products could not be carried over. 

Prior to the general use of mechanical refrigeration for cold 
storage purposes, various food products sold at very low prices at 
the time of high production. This was particularly true of butter. 

A. R. Loomis, of Ft. Dodge, Iowa, told one of the authors 
that at this early period he was able to buy several carloads of 
creamery butter, whole-milk goods, at ii cents a pound. Certain 
seasons of the year are now designated as cold-storage seasons. 

The season which is recognized as that for making butter for 
storage purposes is the period extending from the latter part of 
May to the first of July. This is regarded as the storage season, 
although some butter is stored'at other times of the year as well. 
Practically all butter, however, is stored during the storage 
season, for two reasons: first, there is more butter made at this 
period than at any other time of the year; second, the grass is at 
its best, and the conditions are more favorable for making good 
butter than at any other time. During this period cows are 
usually milked outside and there is less chance for contamination. 
Hence, the best butter of the year is supposed to be made at this 
time. 

Cold storage brings into the market many dealers in butter. 
They are willing to pay good prices in the summer, taking chances 
on making a reasonable profit during the fall and winter months, 
but in this they are sometimes disappointed. In various states 
laws have been enacted to regulate cold storage and prevent the 
possibility of any individual or combination of individuals 
cornering the food products for the purpose of forcing prices 
beyond what will net a reasonable profit. 

A general agitation was started throughout the country by 
women's clubs and other organizations when food prices were 
extremely high. The impression prevailed among many that 
cold storage was responsible for hoarding or cornering of food 
products, but investigations by the Federal Government showed 
that hoarding was not the cause of high prices. Nevertheless, 



COST OF STORAGE 355 

the agitation became so pronounced that both the Republican 
Party and Democratic Party had planks in their platforms asking 
that laws be passed by Congress to regulate cold storage and also 
demanding a limitation of the length of time that food products 
should be held in storage, with requests for branding the same 
as storage products. 

Cold storage has undoubtedly been of greater benefit to the 
farmer than to anyone else, as the fruits he produces as well as 
his poultry, meats and dairy products go into storage. If it 
were not for the fact that these products can be carried over from 
the time when there is an abundant supply to the time of scarcity, 
very low prices would be paid for them. According to the design 
of Nature, milk, cream and almost all other products can be 
produced more cheaply in the summer when grass is abundant, 
than in the winter months. This is an economic problem with 
the producer. There is no extra labor involved in feeding cattle 
during the period when they are on pasture. 

Cost of Storage. — The average length of time that butter 
is kept in storage is approximately five or six months. Very 
little of the butter that is held in cold storage belongs to the 
owner of the cold-storage plant; it is held by many people 
distributed over a wide area. The cold-storage owner rents 
space in the storage plant to dealers for storing their products, 
and he might be termed a landlord renting out space. 

The charges by the cold-storage companies for the storage of 
butter are usually about one-fifth of a cent per pound for the first 
month and one-eighth of a cent per pound for each succeeding 
month. To this must be added insurance charges and interest 
on investment. For the purpose of completing the data for an 
estimate, it will be assumed that the average price of butter for 
storage is 35 cents, and the interest rate 7 per cent. On this basis 
the cost, per pound, of carrying butter in storage for a period 
of six months would be approximately as follows : 

Storage charges, including insurance i cent 

Interest on investment. ij cents 

Total • 2 J cents 



356 COLD STORAGE AND BUTTER FOR STORAGE PURPOSES 

Varying conditions, as length of time in storage, storage rates, 
price of butter and rate of interest, would, of course, modify the 
above estimate. It is a fair assumption to make that the cost of 
carrying butter during the storage season will be from 2 to 2^ 
cents a pound. 

Should Cold Storage Butter be Branded? — A great deal of 
butter is kept in what are known as coolers by the butter dealers 
or merchants. Such butter is termed fresh butter until it is 
placed in cold storage plants. There is a bill before Congress 
at the present time which would require all butter held at a tem- 
perature below 45° to be classified as cold-storage butter. If 
such a bill should become law in its present form, all butter made 
in the creameries would be classified as storage butter as soon as it 
is churned, as all creameries use coolers for keeping their butter 
until it is shipped, when it is placed in refrigerator cars and 
shipped to the dealer. The latter may either place it in cold 
storage or carry it in his cooler from two weeks to sixty days, 
depending upon market conditions. There are a few firms 
who have coolers large enough to store two cars of butter, and 
they can control the temperature of the said coolers to almost any 
desired point. 

The placing of a brand on butter of this character would be 
the means of causing the butter to sell for several cents per pound 
less, due to the prejudice that exists in the minds of many people 
against cold-storage goods of any kind. From a health stand- 
point there is no necessity for placing a brand on butter or cheese 
held in cold storage, for the reason that good butter will keep 
for a very long time without undergoing practically any change, 
if held below zero Fahrenheit. 

Dr. Larson, Chief of the Dairy Division, reports having 
examined butter that was kept for three years in storage and 
which scored as high as 92 points when taken out. Where butter 
is held at a temperature between 5 and 10 degrees below zero there 
is very little danger of any change taking place during a period of 
nine to twelve months, especially if the butter is good. The 
authors know of a specific case in Chicago, where, owing to 
declining prices and in order to avoid a loss, a buyer carried 



BUTTER FOR STORAGE 357 

butter over from one season to the next. This butter was held in 
storage approximately eighteen months, at a temperature below- 
zero, and when taken out of storage it showed little or no deterio- 
ration. Holding this length of time is, of course, not the rule, 
as most of the butter put into storage is not held over six months, 
or at most nine months. 

Butter going into storage and butter coming out of storage 
are both sold by grade. The changes that take place in storage 
butter will depend, to a very large extent, upon the condition of 
the butter when going into storage, also upon the material from 
which it was made and the temperature at which it has been held. 
Butter held at high temperatures deteriorates quite rapidly and 
becomes rancid in time. 

Butter for Storage. — One of the most common defects found 
in butter made from raw cream is what is known to the trade 
as cheesy or fishy flavor. The condition of the material used has 
a direct bearing upon the changes that take place. If butter is 
made from sweet cream, or cream nearly sweet, that has been 
efficiently pasteurized, there is very little danger of its going 
fishy; on the other hand, if the material used is not of good 
quality, the chances will be very favorable to its either becon ing 
fishy or showing other deterioration defects that are found in poor 
storage butter. 

In a large shipment of butter, made at Strawberry Point 
under the direction of one of the authors, the cream used had 
been efficiently pasteurized and its quality was all that could be 
desired in the way of flavor. The butter was held in New York 
in storage for between six and seven months. The average score 
on flavor, when entering storage, was 38.17, and on body 24.88; 
when coming out it was, flavor 38.25 and body 24.92. 

The condition of the material used in the m.anufacture of 
butter, that is, the milk or cream, has a pronounced bearing upon 
the quality of the butter when it comes out of storage. Butter 
made from cream with a low acid and light salt will keep in storage 
better than butter made from cream with a high acid, especially 
if the acid has been developed in the cream without being con- 
trolled by the manufacturer. 



358 COLD STORAGE AND BUTTER FOR STORAGE PURPOSES 

The butter referred to above, which was made at Strawberry 
Point, was made from cream containing .68 of i per cent of acid, 
and it was ripened with a pure culture starter; it must be taken 
into consideration, however, that Strawberry Point at that time 
received whole milk of an exceptionally good quality. The milk 
was inspected on the stand by a man who had been engaged for 
that purpose, and any milk that was sour or tainted was rejected. 
At the present time very little butter is made under what is 
known as the whole-milk system. Possibly 90 to 95 per cent of 
the butter produced in this country is manufactured from so- 
called hand-separator cream. The result is that the producer 
has entire charge of cleansing separators and other utensils 
that come in contact with milk and cream, and some of the 
producers do not adopt the most sanitary methods, in cleansing 
their separators and other utensils used in the dairy. In addi- 
tion to this, there is, in many cases, the neglect to properly cool 
the cream after each separation. Some make a practice of mixing 
the warm cream with the previous lot that was separated without 
cooling, and the cream may also be held for a long time on the 
farm before it is delivered to the creamery or cream-buying 
station. 

To the farmer the delivery of cream involves an economic 
problem. He cannot afford to go daily to the creamery or the 
cream-buying station, and the result is that he holds the cream 
until he has about a can of it, or enough to warrant him in 
making the trip to town. Cream of this character is usually 
more or less sour when it reaches the creamery where it is to be 
manufactured into butter. Some of it is too sour for pasteur- 
ization and the acidity must be reduced. 

Various investigations have shown that butter churned from 
high-acid cream has a tendency to become fishy when placed in 
storage. The use of bad starters has an injurious effect also. 

One of the leading butter houses in New York has instructed 
the creameries sending it butter not to use starters during the 
storage season. Investigations have demonstrated that for 
storage purposes low-acid and light salt give the best results 
under present conditions. 



BUTTER FOR STORAGE 359 

U. S. Bulletin 84, gotten out in 1906, by Gray and McKay, 
gives the results of investigations of the manufacture of butter 
under different conditions, and the keeping qualities of butter 
made under these varying conditions and stored at different 
temperatures. C. E. Gray, dairy expert for the Dairy Division 
at that time, had charge of the manufacturing of the butter, 
which was scored and criticized by McKay and Keiifer. Some of 
the butter for this experiment was made at Topeka, Kansas, 
from sour cream, and some at Monticello, Iowa, from sweet 
cream. The butter made from different lots of cream was divided 
and salted so that it contained from i to as high as 3^ per cent 
salt. It was kept in storage at —10°, 10° and 32° F., and 
placed in the vestibule before being scored, the temperature of 
the vestibule at the time of scoring being 50° to 55° F. After 
the butter had been in the Booth cold storage for eight months, 
it was rem.oved to the Iowa Experiment Station in a refrigerator 
car. It was found that on coming out of storage the butter 
made from sour cream in nearly every case had a pronounced 
fishy flavor, and that butter made from sweet cream containing 
light salt kept much better in storage than the butter made 
from the cream having a high per cent of acid. The two factors 
that gave the best results in this butter were low acidity in the 
cream and low per cent of salt in the butter. 

It must not be understood from the above that it is absolutely 
necessary to have sweet cream to make butter that will possess 
a good keeping quality. Where cream is high in acid and is free 
from any objectionable flavors, its acidity can be reduced by 
limewater or milk of lime. 

Some of the highest-selling butter found in our leading 
markets is made from cream that was originally high in acid, 
the acidity having been reduced and the cream re-ripened with a 
starter. Very poor cream is frequently found to be fairly low in 
acidity. This is due to inoculation with undesirable organisms, 
through neglect of proper care and cleansing of dairy utensils. 
If cream is high in acidity but possesses a clean acid flavor and 
the acidity is reduced, the quality of the butter will be good, and 
it has been demonstrated that butter made from such cream 



360 COLD STORAGE AND BUTTER FOR STORAGE PURPOSES 

vvill come out of storage in good condition. In fact, some of the 
leading butter dealers are now giving a preference, for storage 
purposes, to butter made in the large creameries where the 
acidity of the cream is reduced and the butter is manufac- 
tured under conditions that impart to it a good body and 
texture. The statement made elsewhere, that one of the large 
creameries made 25 miUion pounds of butter last year that graded 
Extras or Specials, demonstrates what can be and is being done. 
However, not all the butter made in large creameries is of this 
quality, owing to lack of care and skill in the manufacturing. 
Improper neutralizing, neglect to churn at a sufficiently low 
temperature and improper working are some of the causes of the 
production of butter of low quality or an inferior grade. 

Working and Packing Butter for Storage Purposes. — Gream 
should be cooled until the fat is chilled to such a point that the 
granules of butter when they gather will be in sufficiently firm 
condition. The butter can then be sufficiently worked to thor- 
oughly incorporate the salt, so that the finished product will not 
contain loose moisture and show up leaky when packed. (See 
chapters on Churning and Working Butter.) 

Butter should be packed very closely in the packages, whether 
box or tub, to avoid air pockets. The tubs or boxes should be 
thoroughly steamed before paraffining, and care should be 
exercised to make sure that all parts of the wood are coated with 
hot paraffin. Care should also be taken to keep tubs and liners 
in a dry place. 

For preparing tubs, boxes and Hners for packing butter, see 
Chapter XIX. 

Some butter is held in storage for more than a year, but it is 
very seldom that very much butter is held over nine months. 

The Navy butter is put up under government instruction and 
is made from sweet cream, or cream containing not more than 
.25 of one per cent of acid, and pasteurized without the use of a 
starter. 

The first to recommend churning the cream sweet was Mr. 
J. D. Leclair of St. Hyacinth Dairy School, Quebec, Canada. 
His method is outlined in a bulletin issued in 1904. The cream 



BUTTER FOR STORAGE 361 

used was from milk separated at the creamery and contained 
nearly 40 per cent fat. After being pasteurized and cooled to 
churning temperature it was held for about three hours. After 
the cream was put into the churn a large per cent (25 to 30 per 
cent) of starter was added and churning followed immediately. 
Butter made in this way secured first place at the leading Cana- 
dian Exhibitions in 1903. The beneficial effects of the use of 
good raw material and a good starter should again be noted. 
Leclair maintains that by adding a starter to sweet cream and 
churning immediately the flavor-producing substance can be 
developed in the butter after it is churned. He says that if 
sweet cream is churned with a portion of sour milk or starter 
the butter will have about the same flavor after standing as it 
would have if the cream were ripened. Some have tried to 
improve the flavor of butter by adding a starter directly to the 
butter and working it in with the salt. According to the Internal 
Revenue regulations, butter of this kind would be deemed 
adulterated and be subject to a tax of 10 cents a pound. 



CHAPTER XXIV 
COOLING FACILITIES FOR CREAMERIES 

One of the most important points in connection with the 
successful operation of a creamery is the control of temperature. 
This control is important in the separation, pasteurization, ripen- 
ing and churning processes, and in the use and preparation of 
starters. Conditions are frequently such that the raw as well as 
finished dairy products need to be stored. If temperature or 
cold storage conditions are not under control, dairy products 
will suffer in quaHty. Raw as well as finished products are very 
perishable and are best when fresh. Strictly. and generally 
speaking, dairy products deteriorate with age, the nearer the 
producers of the raw material, manufacturers, and consumers of 
the finished products can be brought together, the better it is. 
Conditions of commerce and trade are such that butter needs to 
be preserved for some time before it reaches the consumer. 

The preservation of butter depends on the checking of fer- 
mentations affecting the flavor of this product, and can best be 
accomplished by the use of a low temperature. There are various 
ways by which low temperature may be obtained in creameries. 
The system of refrigeration to be employed in a given creamery 
should be determined by local conditions. 

Cooling Systems: 

1. By the use of natural ice. 

2. By the use of mechanical refrigeration. 

3. By the use of cold water alone. 

I. Most local creameries, within the ice-freezing belt, make 
use of natural ice. It is by far the most common method of 
refrigeration employed in creameries, and undoubtedly under 
average local conditions, represents the most economic method 
of obtaining low temperature. As a rule patrons have little 

362 



COOLING SYSTEMS 363 

work to do during the winter and are willing to supply teams 
and help for a few days while the ice is being put up. The use of 
natural ice gives good satisfaction, especially when good, pure 
ice can be had within a reasonable distance from the creamery, 
and a proper and convenient place is provided in which to store 
the ice. 

2. Mechanical refrigeration is undoubtedly gaining favor 
with creamery-men, as is evidenced by the increased number 
of mechanical refrigerating-plants installed in various creameries. 
The reasons for this increase are due, first, to centralization of 
creameries, second, to mild winters in certain sections and a con- 
sequent lack of natural ice, and third, to the greater convenience 
of mechanical refrigeration if properly operated. 

CentraKzed creameries have so much more cooling to do 
than a local creamery, that a mechanical refrigerating-plant 
best serves their needs. Often centralized plants are located in 
large cities where an ice-manufacturing plant and cold storage 
plant may be run successfully in connection with the creamery. 
Prof. Erf 1 has conducted some experiments relative to the com- 
parative cost of the two systems for creamery use. The fol- 
lowing table shows the results, and indicates the comparative 
cost of cooling loo pounds of butter to 30° F., including the 
cost of cooling the cream during manufacturing processes. 
These figures are also based upon a run of 10,000 pounds of milk 
per day. 

1234 
Cents Cents Cents Cents 

Natural-ice system 20.1 18.2 17.5 17. i 

Mechanical refrigeration 17.8 17. i 16.9 16.8 

The different columns (i, 2, 3, 4) indicate different insulating 
material used, which cannot here be elaborated upon, except 
to say that it pays to insulate thoroughly. 

The above results indicate that mechanical refrigeration is a 
little the cheaper. Its cost is quite constant under different 
conditions, while the cost connected with storing and using nat- 
ural ice will vary greatly according to different localities. 

^ Creamery Journal. 



364 COOLING FACILITIES FOR CREAMERIES 

3. Under certain conditions, intentional or unintentional, a 
creamery must be run without the use of ice, and without 
mechanical refrigeration. In such a case cold water is a necessity. 
One of the authors successfully operated a creamery for one 
season without any other cooling agent than water. The winter 
season had been warm and no ice was obtained nor was it obtain- 
able at a reasonable cost. There was no room in the creamery 
for a mechanical refrigerating-plant, and even if there had been, 
no money was available with which to purchase such cooling 
facilities. The only thing to do was to close the creamery or cool 
with water. 

The latter method was resorted to. The creamery was 
fortunate in having an unlimited supply of pure cold water 
coming from a mountain stream. 

This water was made effective for cooling purposes by 
directing a constant flow through a galvanized iron tank in the 
refrigerator. The ice-box on the inside of the refrigerator was 
removed, and a closed galvanized iron tank put in its place. 
This tank was connected with an inflow and overflow at the top. 
A faucet for draining the tank was provided at the bottom in one 
corner. The tank was made straight on the side next to the wall, 
but sloping towards the wall on the side facing the refrigerator 
room. This was done so as to allow the dampness or sweat col- 
lecting on the outside to run down the sides and be collected in a 
trough, which conveyed it to the outside. A trap was connected 
with this outlet so as not to let in warm air. Such an arrange- 
ment gave very good satisfaction, though not so effective in 
cooling as ice. 

The cream was cooled and kept cold by circulating a constant 
stream of water through the vat-jackets. The temperature of 
the water was never above 50° F. 

The butter was disposed of locally while fresh. In cream- 
eries where it is necessary to hold butter any length of time, this 
system is undoubtedly less satisfactory, but under the above- 
mentioned conditions it gave good satisfaction. 

The water-tank should never be made from wood, as wood 
is a very poor conductor of heat. Heavy galvanized iron is best. 



NATURAL ICE SYSTEM 365 

NATURAL ICE SYSTEM 

Kind of Ice-house. — When natural ice is stored, the first con- 
sideration is a good ice-house conveniently located to the cream- 
ery and refrigerator. When the creamery is first planned and 
built the ice-house should at the same time be provided for. 
It should preferably be adjacent to the refrigerator, so that the 
ice can be transferred directly from the house into the cooler, 
thus obviating much loss of ice and decreasing labor. 

The various parts of the building, embracing the many 
details, will not here be enlarged upon, inasmuch as they can 
be more advantageously shown in plans. Students are referred 
to the different views shown in this chapter. 

. As will be seen, the construction of the ice-house depends 
to some extent upon the location and kind of refrigerator to be 
used. There are at least two different ways of locating the 
refrigerator in relation to ice-house: (i) Where the refrigerator is 
entirely separate from the ice-house, the ice to be transferred 
and placed either overhead or on one side of the refrigerator. 
(2) Where the refrigerator is combined with the ice-house and the 
ice is not moved for cooling purposes. This in turn may be 
arranged so as to have the ice storage overhead or on one side of 
the refrigerator. The ice-house needed in connection with this 
second method differs chiefly from that of the first in that better 
insulation is necessary and no ice-packing material is used, except 
on top. This latter type of creamery refrigerator, even though 
more expensive, is to be highly recommended, chiefly because 
labor is decreased, and the low temperature is uniformly main- 
tained. 

Reasonably high ground affords a good location for an ice- 
house. It is of importance that the ground should be thoroughly 
drained before the ice-house is built. If the ground is high, dry, 
and gravelly, no drainage may be needed, but under most con- 
ditions a drain should be run through the bottom. This drain 
should not be very deep. If the area to be drained is so large 
that one drain will not carry off the water, it is better to use two 
drains rather than to have one deep one. 



366 



COOLING FACILITIES FOR CREAMERIES 



r@ 



Space be^een 8tudB\filled witMBhftTlngi 



Drain -^ 



Cooling Koom 




PLAN 



Second or Attic Floor 




SECTION 
Fig. 129.— Refrigerator with ice overhead. 



NATURAL ICE SYSTEM 



367 




368 



COOLING FACILITIES FOR CREAMERIES 



Size and Shape of Ice-house. — The plan of the ice-house 
should be as nearly square as consistent with available space. A 



% i 6 D. & M. Fencing. 

Waterproof Paper, 
% Surfaced Boarda. 



% Surfaced Boards. 
- ,^ Waterproof Paper, 
;/ X s'd, & M. Fencing. 




Gravel under joists well 
tamped 



Fig. 131, — Construction detail of ice-house, 
square building, having a certain length of wall around it, will 
hold more ice than an oblong building having an equal number of 



NATURAL ICE SYSTEM 369 

feet of outside walls. The building should also be high in pro- 
portion to width and length. This will tend to preserve the ice, 
as proportionately less top surface is exposed to the air. 

The size of the building will vary according to (i) amount 
of milk handled at the creamery, (2) whether ice is sold from 
creamery, and (3) whether ice is used for any other purposes, 
such as ice-cream freezing, cream shipping, etc. For creamery 
uses, the only basis on which to estimate is the amount of milk 
received. 

For example, suppose a creamery is receiving 12,000 pounds 
of milk daily. This milk will produce about 2000 pounds of 
cream and about 6co pounds of butter. Suppose that the 
cream needs to be cooled from 90° F. down to 40° F. or a range 
of 50° F. One pound of ice will cool about 142 pounds of water 
1° F. Calculations are made with water as basis. The results 
will thus be a little too high, but subsequent corrections will be 
made. If i pound of ice will cool 142 pounds of cream 1° F., 
it will require 50 pounds of ice to cool that amount of cream 50° F. 
By calculation from these figures we find that about 0.35 of a 
pound of ice is required to cool each pound of cream 50° F. and 
for cooling 2000 pounds of cream it will require 700 pounds. If it 
takes 700 pounds of ice daily for cooling the cream for eight 
months of the year, which is about the time the cream would have 
to be cooled by artificial means, it would take 168,000 pounds of 
ice per year. As the specific heat of cream is only about 0.7, 
the final amount needed for cooling the cream would be only 
117,600 pounds, or about 59 tons. 

The next consideration is the ice needed for cooling the butter. 
Roughly speaking, there will be about 6co pounds of butter. 
Suppose the butter needs to be cooled 30° F. Granting that the 
specific heat of butter is the same as that of water, it would 
require 30 pounds of ice to cool 142 pounds of butter 30° F. 
There will therefore be needed daily 1 26 pounds of ice for cooling 
the butter. As the specific heat of butter is only about 0.4, 
51 pounds of ice are necessary daily. For eight months 12,240 
pounds will be needed. The amount of ice needed in a refrigerator 
above that needed for cooling the butter cannot be calculated. 



370 



COOLING FACILITIES FOR CREAMERIES 



We may count on 25 per cent radiation and 25 per cent as an 
allowance for cooling tubs and packages. The total ice needed 




for cooling the butter will then be 24,480 pounds, or about 12^ 
tons. 



NATURAL ICE SYSTEM 



371 



Counting on 20 per cent loss incidental to transportation 
and melting in the ice-house, 89 tons of ice are needed for cooling 
the cream and butter the number of degrees mentioned above. 




One cubic foot of ice at 32° F. weighs 57.5 pounds. If i 
cubic foot of ice weighs 57.5 pounds, 89 tons would occupy a 
space equal to 3093 cubic feet, and would require an ice-house of 
dimensions approximately as follows: 16 feet high, 14 feet wide, 



572 COOLING FACILITIES FOR CREAMERIES 

and 14 feet long. These dimensions are given only as examples. 
The height, width, and length may need to be changed to con- 
form with local conditions. One thing should be kept in mind — 
it is always better to have an ice-house a little too large rather 
than too small. 

Filling the Ice-house. — The chief objects to be sought in 
packing ice into an ice-house already properly constructed, 
are: first, to exclude circulation of air through the mass of ice 
and thus prevent melting; second, to pack it in such a manner 
that it can easily be removed in whole blocks; third, to pack 
it with material that will leave the ice as clean as is consistent 
with other important objects sought. 

The packing material which is most commonly used in the 
central western states is sawdust. This is very efficient in 
excluding air, lasting, and usually cheap, but soils the ice 
so that considerable -Water iieeds to be used to rinse it, and as a 
consequence, considerable ice is wasted. Straw is used success- 
fully. It leaves the ice much cleaner, but is not so effective in 
preserving the ice. Shavings are good, but as a rule are too 
expensive and not available. Some use no packing material 
other than ice and snow. When the blocks of ice are put into 
the ice-house, they are packed closely together. A man with a 
hatchet chips the blocks of ice in such ^ a way as to fit them 
snugly together, and the small cracks are filled with fine ice and 
snow. The experience of the authors is that, by this method, 
the blocks of ice are hkely to freeze solidly together, so that the 
ice cannot be removed without breaking it up iritb irregular 
pieces. This is hard work, and considerable ice is 'Cvasted. 

Another method of filhng ice-houses in successful use is that 
of running a shallow layer of water into the building and allowing 
it to freeze. The doors in the ice-house are opened during a 
protracted period of cold weather. The bottom of the ice- 
house is covered with building-paper. Water is run on top of 
this and allowed to freeze until a layer of ice about a foot in 
thickness has been obtained. Then another layer of paper is 
made to cover the ice and more water flooded on and frozen. 
This process is continued until the ice-house is filled. The papei 



NATURAL ICE SYSTEM 373 

between the layers prevents the ice from freezing into one solid 
mass, and facilitates its removal. 

When the ice is stored in an insulated house, combined with 
the refrigerator, no packing material is used except on the top of 
the ice. Shavings are good to pile on the top of ice when the 
ice-house has been filled. They are clean and effective in pre- 
serving the ice. 

The cost of filling an ice-house with natural ice, obtainable 
within a distance of about 8 miles, will vary in different localities, 
but may be said to range between $0.60 and $1.25 per ton. The 
creamery furnishes a man to pack it into the ice-house. 

Source of Ice. — The ice for creamery use should be obtained 
from as pure water as possible. A large running stream is always 
better than a small polluted stream. Usually the creamery can 
co-operate with butchers, restaurants, hotel-men, and other 
local ice-users in building a dam in a suitable stream. The ice 
can also as a rule be harvested cheaper by co-operation. 

Some creameries have constructed ice-ponds near the ice- 
house. If there is a clay or impervious bottom, this works suc- 
cessfully and economically. The pond is filled and kept filled 
from the creamery water-supply or from a tile drain inlet. 
Care, should be taken not to use stagnant water or water in which 
weeds and other rubbish have been allowed to accumulate. 
The pond should be deep enough so that the water will not freeze 
to the bottom and produce dirty ice. The pond should also be 
filled with water to overflowing when freezing is begun; other- 
wise slush and snow are likely to accumulate together with dust 
from the fields and roads, producing impure ice. 

The ice is best when frozen from the top down. A hole is 
bored in the ice and kept open during the freezing process. 
Through this opening the pond is supplied with water as rapidly 
as it subsides. When the water is solidly up against the bottom 
of the ice it will show in the opening or hole in the ice. 

To construct an ice-pond on gravelly soil is useless, and to 
pack such a pond with a sufficiently thick layer of clay to 
prevent leakage of water is, under most conditions, imprac- 
ticable.- 



374 COOLING FACILITIES FOR CREAMERIES 

USE OF ICE IN COOLING CREAM 

1. Directly. 

2. Indirectly. 

1. The cooling of cream in creameries by putting ice directly 
into the cream has been much practiced in the past. The 
method is yet used considerably, especially where the old open 
vats are still in use. Some of these open vats are jacketed 
and some are not. Cream in unjacketed vats could not well 
be cooled in any other way than by using ice directly in the 
cream and stirring until cold. To keep cold any length of time, 
considerable excess of ice needs to be used. 

Such a method of cooling cream has its advantages as well as 
disadvantages. The latter, however, clearly outweigh the former. 

The advantages are that the cream can be cooled in a very 
short time, and it does not require any special investment 
for up-to-date ripening-vats, nor special machinery for the pur- 
pose of pumping the cooling medium. 

The chief disadvantages are : first, impurities and undesirable 
germs are liable to be introduced, which injure the quality of 
the cream and otherwise work harm to the quality and keeping 
property of the butter; second, the melting of the ice would dilute 
the cream. This would render the cream less sour, impart a 
marked fiat, insipid taste to the cream and butter, and produce 
more buttermilk which, if it contained a certain per cent fat, 
would mean a greater loss of fat during the churning process. 

The use of ice directly in the cream for coohng purposes 
should not be resorted to unless it is necessary. With the 
best quality of cream this method is still more unsatisfactory, 
as it greatly lowers the quality of the butter. With cream in 
very poor condition previous to ripening, the chances for lowering 
the quality of butter are not so great. 

2. The indirect cooling of cream with ice is by far the better 
method. With the use of our up-to-date ripening-vats, the 
cooling of cream is an easy matter; but where the creamery is 
already in possession of a good open vat and the management not 
disposed to discard it to install a new one, the question is different. 



MECHANICAL REFRIGERATION 375 

Some open vats have a jacket and special open space at one 
end for holding crushed ice. These vats will control and hold 
temperature better than those that simply have a jacket around 
them. The coohng of cream on a large scale by circulating ice- 
water through the jacket is, at best, a slow process, usually too 
slow to be effective and practical. 

This cooling process is carried out by mixing the ice and 
water together in a separate vat to which a rotary pump is 
attached, forcing the water through the jacket and again return- 
ing it to the ice and water- tank to be cooled. The slowness of 
this cooling process can in a measure be overcome by mixing salt 
with the ice and water. This will cause the ice to melt faster, 
and consequently cool the brine to a lower degree of temperature 
than it is possible to obtain with water and ice. 

In case it is desirable, a set of coils can be made which will 
fit into the open vat. The inlet and outlet of these coils can be 
connected by means of rubber hose with the pipes conveying the 
brine to and from the ripener. The coils can be made to move 
up and down, by means of a rope attached to and leading from 
the coils through a pulley near the loft and fastened to a small 
crank at the end of a shaft. When the shaft turns the crank 
will also turn and cause the coils in the vat to move up and down. 
In the absence of a special up-to-date ripener, this manner of 
cooling works very satisfactorily. 

A butter refrigerator containing a tank, as already described, 
could be cooled by pumping brine through it in a similar 
manner, as described for cream cooling, except that no coils are 
needed. 

MECHANICAL REFRIGERATION 

Application in Creameries. — Mechanical refrigeration on a 
small scale has been considered expensive and impracticable 
until within recent years. The science of producing cold arti- 
ficially has been simplified and reduced to such a practical 
basis that it is now used in many large plants as well as in smaller 
plants where formerly natural ice was used altogether. Where 
at least 10,000 pounds of milk, or its equivalent in cream, 



376 COOLING FACILITIES FOR CREAMERIES 

are received daily during the summer months, mechanical 
refrigeration is considered practicable. 

On another page a table of comparative costs of natural ice 
and mechanical refrigeration is given. It was also stated in 
that connection that the cost of mechanical refrigeration would 
vary under different conditions. The chief factors affecting the 
cost of mechanical refrigeration may be said to be similar to those 
affecting the economic running of the remaining machinery, such 
as kind of fuel used, skill of firemen, style and condition of boiler, 
proportion of boiler power to work done, the correlative size of all 
machinery, kind of insulation and care of cooling-rooms, and 
efficiency of compressor and whole refrigerating system. 

Chemicals Used for Mechanical Refrigeration. — The most 
common substances used in mechanical refrigeration are ammo- 
nia and carbonic acid. A number of others are in use, but 
from a creamery standpoint, these only are of importance. 
Ammonia is the most used. It is efficient, cheap, and not so 
dangerous to life and property as are some of the' others. Anhy- 
drous ammonia has a boiling-point of 27° below zero at atmos- 
pheric pressure. The latent heat of ammonia is also great. 
Ammonia has great chemical stability, and is not explosive in 
nature ; it attacks copper and brass, but has no effect upon iron 
and steel pipes. If ammonia should escape through a leak into a 
room, the operator can protect himself from the effects of the gas 
by breathing through a wet sponge held in the mouth. Ammonia 
leaks may be detected by holding a glass rod dipped in hydro- 
chloric acid to the place where the leak may be. When ammonia 
comes in contact with hydrochloric acid, white fumes are 
formed. 

Carbonic acid is used considerably in Europe, and is chiefly 
favored because the gas is not highly poisonous; in case of 
leak it does not soil contents of refrigerator, and it liquefies 
at a high temperature (90° to 100° F.), and is therefore favored 
in tropical climates. 

Principles of Producing Cold Artificially. — The chief principle 
involved in producing artificial cold is that when a substance 
passes from a liquid into a gaseous state, a definite amount of 



MECHANICAL REFRIGERATION 377 

latent heat is absorbed. When water in a kettle on the stove 
begins to boil and passes off into steam, no higher temperature 
can be reached. No matter how much heat is appHed under 
those same conditions, the temperature remains the same. This 
extra heat is used in transforming the water into steam. If this 
steam were confined, and that heat removed, by cooling, the 
steam would again pass into a liquid state. We are familiar 
with the coolness produced by rapid evaporation of perspiration 
from the body. Mechanical refrigeration is virtually a process 
of evaporation of the cooling media, during which heat is absorbed, 
and liquefaction of the cooling medium by compression and cool- 
ing to remove that absorbed heat. To increase the ability of the 
cooling medium to absorb heat it is compressed and liquefied. 
So it may be said that in any compression refrigerating system 
three separate operations are necessary to form the complete 
cycle of mechanical refrigeration, viz. : 

1 . Compression of the ammonia gas. 

2. Condensation of the ammonia gas. 

3. Expansion of the ammonia gas. 

1 . The machine which causes the compression of the ammonia 
gas is called the compressor. In construction it is much like a 
steam-engine. Small machines are single, but large machines are 
double acting. Gas is drawn in, on the suction stroke, com- 
pressed and discharged on the return stroke. The pressure gen- 
erated varies between 120 and 175 pounds per square inch. 
During the compression heat is developed in proportion to pres- 
sure exerted. The greater the pressure the higher the tempera- 
ture of the gas. Part of the heat of compression is carried off by 
means of a continuous stream of water running through a jacket 
around the cylinder. 

2. From the compressor the gas is forced through the pipes 
into the condensing coils, in which the warm compressed gas is 
cooled still more. When sufficient heat has been removed from 
this gas, it assumes a liquid condition and is ready to expand into 
a gaseous form for the purpose of absorbing heat and producing 
cold. During the cooling and condensing processes each pound 
of ammonia parts with about 560 units of heat, which amount 



378 COOLING FACILITIES FOR CREAMERIES 

can again be absorbed when it expands into gas at the lower 
pressure. 

3. This Hquefied gas, which is still under great pressure, is 
then admitted through what is termed the expansion-valve. 
This valve is especially constructed for that purpose, and has 
only a very minute opening in it for the admission of the liquid 
ammonia. On the expansion side the pressure is low (20 to 
30 pounds). As the liquid ammonia emerges from the high- 
pressure side through the expansion-valve into the expansion 
side, it forms a gas. This expanded gas may then be circulated 
through coils for cooling purposes. From there it passes back 
into the suction side of the compressor ready to go through 
another similar cycle. 

From the above description it will be seen that there are two 
sides to the system, the expansion side and the compression 
side. The compression side extends from the compressor to 
the expansion- valve ; the expansion side from the expansion- 
valve to the suction side of the compressor, inclusive. 

Transferring the Cold. — The methods of transferring the cold 
to the different places in the building vary. There are two sys- 
tems, viz.: 

1. Direct Expansion. 

2. Brine System. 

1. By the direct-expansion system the condensing-pipes are 
extended to the room or place at which the cooling is to be done. 
An extended set of expansion coils then convey the gas which 
absorbs the heat. A lower temperature can be produced by this 
method than with the brine system. 

2. In the brine system a large brine- tank is placed some- 
where in the creamery at a place most convenient with respect 
to cooling. This tank contains a strong solution of brine. The 
chief reason why brine is used in preference to water is that 
brine has a very low freezing-point. This will vary with dif- 
ferent degrees of saturation. 

Either one, sodium chloride (common salt), or calcium 
chloride, may be used for brine. The latter is considered the 
better chiefly because it is not so hard on the pipes and it keeps 



MECHANICAL REFRIGERATION 



379 



the brine pipes cleaner than does a salt brine. The tables give 
properties of brine made from these two substances. 

SHOWING PROPERTIES OF SOLUTION OF SALT. (SIEBLY). 
(Chloride of Sodium). 



Per Cent 

of Salt by 

Weight 


Pounds 
Salt per 
. Gallon 
of Solu- 
tion 


Degrees 
on Sal- 
ometer 

at 60° F. 


Weight 
per Gal. 
at 39° F. 


Specific 

Gravity 

at 39° F. 

4°C. 


Specific 
Heat 


Freezing- 
point, 
Fahr. 


Freezing- 
point, 
Celsius 


I 


0.084 


4 


8.40 


1.007 


0.992 


30.5 


- 0.8 


2 


0. 169 


8 


8 


46 


1-015 


0.984 


29-3 


- 1-5 


2.5 


0. 212 


10 


8 


50 


1. 019 


0.980 


28.6 


- 1.9 


3 


0.256 


12 


8 


53 


1.023 


0.976 


27.8 


- 2.3 


3-5 


0.300 


14 


8 


56 


1.026 


0.972 


27.1 


- 2.7 


4 


0-344 


16 


8 


59 


1.030 


0.968 


26.6 


- 3-0 


5 


0.433 


20 


8 


65 


1.037 


0.960 


25.2 


- 3-8 


6 


0-523 


24 


8 


72 


1-045 


0.946 


23-9 


- 4-5 


7 


0.617 


28 


8 


78 


I 053 


0.932 


22.5 


- 5-3 


8 


0.708 


32 


8 


8S 


1 .061 


0.919 


21 . 2 


- 6.0 


9 


0.802 


36 


8 


91 


1.068 


0.905 


19.9 


- 6.7 


10 


0.897 


40 


8 


97 


1.076 


0.892 


18.7 


- 7-4 


12 


1.092 


48 


9 


10 


1. 091 


0.874 


16.0 


- 8.9 


15 


1.389 


60 


9 


26 


1. 115 


0.855 


12.2 


— II.O 


20 


1.928 


80 


9 


64 


1-155 


0.829 


6.1 


-14.4 


24 


2.376 


96 


9 


90 


1. 187 


0.795 


1.2 


-17-1 


25 


2.488 


100 


9 


97 


1. 196 


0.783 


0.5 


-17.8 


26 


2.610 


104 


10 


04 


1. 204 


0.771 


— 1. 1 


-18.4 



PROPERTIES OF SOLUTION OF CHLORIDE OF CALCIUM. (SIEBLY) 



Per Cent by 


Specific Heat 


Specific 
Gravity at 60° 


Freezing-point 


Freezing-point 


Weight 




Fahr. 


in Degrees Fahr. 


in Degrees Cels. 


I 


0.996 


1.009 


31 


- 0.5 


5 


0.964 


1-043 


27-5 


- 2.5 


10 


0.896 


1.087 


22 


- 5-6 


15 


0.860 


I -134 


15 


- 9.6 


20 


0.834 


1. 182 


5 


-14.8 


25 


0.790 


1.234 


- 8 


— 22.1 



380 COOLING FACILITIES FOR CREAMERIES 

The expaiasion-coils pass through the brine-tank and cool 
the brine. Special pumps force the cold brine through pipes 
to the cream vat, cooling coils, ice-cream freezer, etc. 

For creameries the brine system is the only practical system. 
It is preferred because, first, cold can be stored in an insulated 
brine-tank and used at will without running the compressor. 
(In case of a prolonged stoppage due to some accident a brine 
made by a mixture of ice-water and salt could be temporarily 
substituted); second, less ammonia is required to charge .the 
system; third, fewer couplings and less ammonia pipes are 
necessary. This latter would decrease the danger of ammonia 
leakage and cost of pipes. 



CHAPTER XXV 
ECONOMIC OPERATION OF CREAMERY 

Inasmuch as it is impossible within the Kmited space of this 
work to enter upon a detailed discussion of the various principles 
and practices of operating boilers, engines, mechanical refrig- 
erators, and other creamery machinery, only a few of the chief 
factors cornmon to creamery practice and affecting economic 
operation shall be discussed here. For more complete informa- 
tion students are referred to works treating specially of these 
phases. 

Firing the Boiler. — Much fuel can be wasted or saved accord- 
ing to the completeness with which the combustion occurs. 
This again depends upon the manner of firing, upon the regula- 
tion bf the draught, and upon the kind of boiler. The fire 
on the grates should never be too thick nor should too much 
coal be loaded on the fire at any one time. A thin, even fire 
permits of a more complete combustion than is possible when 
clinkers and cinders are allowed to accumulate on the bottom of 
the fire and a heap of unburned coal on top. By this latter 
method of firing, the grates are likely to be injured. 

To get the most heat from the coal the draught should be 
regulated. The combustible part of the coal is of two kinds: 
first, the fixed carbon, and second, the volatile matter. The 
former is the coke or the part of coal which is seen on the grates 
as a mass of glowing fire. The latter consists of the gases which 
pass off when a certain temperature is reached, and which, when 
mixed with a certain amount of air at a given temperature, will 
burn. The heavy black trail of smoke seen rising from chimneys 
is partially wasted coal. If the grates are choked with a thick 
fire, no air can pass through, and the volatile parts of coal pass 
oft" without being burned. 

381 



382 



ECONOMIC OPERATION OF CREAMERY 



Burning Wood or Coal. — In some localities this question is 
of minor importance, as conditions may be such that coal only 
can be used. In other sections, where both are obtainable, it 
is of great importance. The following table ^ shows figures 
obtained at five factories in Wisconsin where soft coal was burned 
and five others where wood was used. 

DAILY FUEL USED AT SEVERAL CREAMERIES 



Pounds of Milk 
Skimmed 
per Day 



3,500 
8,000 
23,000 
6,000 
5^300 



Pounds of 

Soft Coal 

Burned 



500 
400 
1000 
300 
500 



Cost of Coal 


per 


Ton 


$3 


55 


3 


00 


4 


05 


3 


50 


3 


15 



Estima 


ted Cost 


per 


Day 


$0 


90 





60 


2 


00 





50 





80 



Pounds of Milk 
Skimmed 
per Day 


Cords of Wood 
Burned 


Price per Cord 


Estimated Cost 
per Day 


2,000 
3,400 
6,500 
3,800 
4,500 


1 

1 

1 

6 

1 
3 


$1.25 
2.25 
1.25 
2.25 
1.80 


$0.32 

0.37 
0.32 

0.37 
0.60 



These are the best obtainable figures of comparison under 
creamery conditions. 

If wood is burned the dryness of it is an important considera- 
tion. If the wood is wet its power of producing heat is greatly 
lessened, as a certain amount of heat is used in evaporating the 
water in the wood. Air-dry wood will contain from 12 per cent 
to 25 per cent water. The quality of coal is another variable 
factor. In general, and from the table which follows, it might be 
said that 2^ pounds of wood are equal to i pound of lump coal. 



Farrington in Hoard's Dairyman. 



DAILY WEIGHING OF COAL USED 383 

The following comparative table is given by Kent: 

Hickory or hard maple, weight per cord 4500 lbs. = 1800 to 2000 lbs. of coal. 

White oak, weight per cord 3850 lbs. = 1540 to 1715 lbs. of coaL 

Poplar, chestnut and cedar, weight per cord 2350 lbs.= 940 to 1050 lbs. of coal. 
Pine, weight per cord 2000 lbs.= 800 to 925 lbs, of coal. 

Whether a creamery can economically use slack or lump coal 
is another question worth considering. Slack coal is used very 
little in local creameries, mainly because it is more difficult to use 
in firing. Usually help is scarce, and coal which requires less 
attention in firing is preferred. In the second place slack coal is 
subject to spontaneous combustion and likely to set buildings 
afire. Some, if not all insurance companies, discriminate against 
creameries using slack coal as fuel. Thirdly, special grates 
(rocking grates) are essential to get best results from using slack. 
Fourthly, slack coal is dirty and the dust from it will lodge all 
over in the boiler and engine room. 

Slack coal, where conditions are at all favorable for its use, 
is, as a rule, cheap to burn. According to experimental data, 
I pound of slack coal will produce about 4 pounds of steam, 
and I pound of lump coal will produce about 6 pounds of steam. 
The price of the two will vary, but usually the relation is, slack 
coal, $1.25 per ton; lump coal, $3.25 per ton. If i pound of lump 
coal produces 6 pounds of steam, a ton will produce 12,000 
pounds. If I pound of slack coal produces 4 pounds of steam, 
to produce 12,000 pounds will require 2992 pounds of slack coal, 
which would cost $1.87. The difference in producing 12,000 
pounds of steam in favor of slack coal would then be $1.38. 

Daily Weighing of Coal Used. — The advantage of daily 
weighing of coal used in creameries carmot be too strongly 
emphasized. That business phase of creamery work has been 
much neglected in the past. If the coal used daily is not weighed, 
a serious loss or leak may continue without detection. Firing 
the boiler is a daily occurrence, and if a small loss occurs, the total 
loss at the end of the year will cut short the profits. 

The weighing can be done conveniently by fitting a box 
similar in shape to an enlarged flat-sided curd pail on a pair of 
platform scales. After the scale and box have been purchased 



384 ECONOMIC OPERATION OF CREAMERY 

there are no additional expenses and very little extra labor 
required. 

Cleaning the Boiler. — The amount of coal used will vary with 
several factors, viz., cleanliness of flues, sediment in the boiler, 
condition of fire, kind of boiler, steam leaks, pipe insulation, etc. 
The two first factors are frequently neglected. The flues should 
be cleaned every morning before the day's run. The inside of 
the boiler should be kept clean. Heavy scale on the inside of the 
boiler and flues, and heavy sediments on the bottom of the boiler, 
should never be allowed to accumulate. Some water naturally 
contains a large amount of minerals and leaves a heavy deposit 
in the boiler. The operator should learn to know the condition 
of the water, and the frequency of cleaning the inside of the boiler 
should be governed accordingly. One cleaning per month is 
sufficient with most water. In some instances, one cleaning per 
week is necessary. 

The collection of scale and sediment within the boiler affects 
the economic operation in at least three ways: First, more fuel 
is needed; second, the boiler itself is likely to warp; third, 
foaming or priming of the boiler is likely to occur. If scale 
clings to the flues when washed, it may be removed by putting 
some sal-soda and water into the boiler and boiling for several 
hours. Some use a boiler compound for preventing scales. 
This is not necessary nor to be recommended except in extreme 
cases where the mineral content of the water is very high. The 
boiler should be frequently blown off at low pressure. 

Priming of Boilers. — When considerable water passes over 
with the steam the boiler is said to be priming. This water in the 
steam interferes with the running of the engine, filling the engine- 
cylinder and resulting in broken piston or cylinder-head. The 
engine jerks and thumps to such an extent that there is danger of 
breaking other parts of the machinery. 

The foaming or priming of boilers is due chiefly to: 

1. Too much water in the boiler. 

2. Working the boiler beyond its capacity. 

3. Allowing mud and minerals to accumulate in boiler.' 

4. Using too much of certain boiler compounds. 



THE INJECTOR 385 

5. Using water which naturally contains a large percentage 
of certain minerals conducive to foaming. 
The Injector. — The injector on the boiler frequently causes 
the operator some annoyance by refusing to work. The common 
causes of this are: 

1. Too low boiler steam pressure. 

2. Steam obtained from a pipe already supplying steam for 

other purposes. 

3. Leaks in suction pipe due to shortage of supply pipe 

or holes in pipe. 

4. Too hot supply water. 

5. Scale in injector, preventing proper working of valves. 

6. Steam containing too much water. 

Oil-separators. — Considerable saving can be accomplished in 
a creamery if the exhaust steam is utilized. This steam may be 
used for pasteurizing the skim-milk, for heating the milk previous 
to separation, for heating the creamery, and for heating the water 
for the boiler. 

The exhaust steam contains considerable oil and should be 
purified before it is used for any other purposes. Several forms 
of steam purifiers are on the market. They are simple, inexpen- 
sive, and can be attached to the exhaust-pipe of any engine. 

All steam and water pipes should be carefully drained in the 
winter to prevent freezing. 

Belt, Pulley and Speed Calculation. — The length of a belt 
may best be determined by measuring over the two pulleys 
with a tape or a string. 

To calculate the size of a drive pulley when the speed of it is 
known the diameter of the driver pulley is multiplied by its speed 
and the product divided by the speed of the driven pulley, the 
quotient will be thg diameter or size of the needed pulley. 

To calculate the speed of a driven pulley, multiply the 
diameter by the speed of the driver pulley and divide the product 
by the diameter of the driven pulley; the quotient is the speed or 
number of revolutions per minute. 



APPENDIX 



LEGAL STANDARDS FOR DAIRY PRODUCTS, 1920 



States 



Alabama 

California 

Colorado 

Connecticut 

District Columbia . 

Delaware 

Florida 

Georgia 

Hawaii 

Idaho 

Illinois 

Indiana 

Iowa 

Kansas 

Kentucky 

Louisiana 

Maine 

Maryland 

Massachusetts ... 

Michigan 

Minnesota 

Missouri 

Montana 

Nebraska 

New Hampshire. . 

New Jersey 

New Mexico 

New York. 

North Carolina.. . 
North Dakota. . . 

Ohio 

Oklahoma 

Oregon 

Pennsylvania .... 

Porto Rico 

Rhode Island .... 
South Carolina. . . 
South Dakota. . . . 

Tennessee 

Texas 

Utah 

Vermont 

Virginia 

Washington 

Wisconsin 

Wyoming 



Total 
Solids 



II. 75 
12. S 

12. IS 

12. S 

13 



12. 5 

12 . 2 

None; 



Solids 
Not 
Fat 



5 12.5 



Fat 



9 
munici 



.25 
.25 

■ 5 
.25 

5 

■ 35 



3 

3-2 

3 

3 

3 

3-2 

pal con 

3 

2.5 



Skim- 
milk 



Total 
Solids 



% 

None; 

9-25 

9-25 

9-3 

None; 

None; 

9-2S 

9-25 
9-25 
9-25 



9-25 
8.00 



9-3 
Sp.gr. 

32 



9 
None; 
9-25 



trol 



None; 
9-25 



9-25 

9-3 

9 



Cream 



Fat 



%. . 
munici 



munici 
munici 



IS 

20 

i8 
15 
i8 
i8 
i6 
munici 

"i& 
IS 

"i& 

20 

15 



Butter 



Whole- 
milk 
Cheese 



Fat 



% 
pal con 
So 
82.5 

2 83 
pal con 
pal con 

82. S 

82.5 
82. 5 
82. 5 
80 

82. 5 
82. 5 



82.5 

80 
pal con 

82. s 



pal con 
80 
82. s 



82.5 
80 



Total 
Solids 



% 
trol 
30 
35 



trol 

trol 

50 

I30 
SO 
50 



50 
50 



45 
50 



trol 
450 



trol 
450 
450 



'50 
30 
50 



Condensed 
Milk 



Total 
Solids 



24-5 
28 



Fat 



% 

7.7 
7-7 



7 

7-7 
7.7 
7-7 



7.7 
7-7 



7 
4-5 



7-7 
7.7 



7 
7.7 



1 Per cent of fat. 

2 Not over 12 per cent water or s per cent salt. 

3 Proportion of fat to total solids must be the same as in the crude milk. 

4 Per cent of fat in total solids. 
> May and June, 12. 

387 



388 APPENDIX 

METRIC SYSTEM 1 

METRIC SYSTEM OF WEIGHTS AND MEASURES AND 
TABLES FOR THE CONVERSION OF METRIC 
WEIGHTS AND MEASURES INTO CUSTOMARY 
UNITED STATES EQUIVALENTS AND THE REVERSE. 

In the metric system the meter is the base of all weights and 
measures. 

The meter was intended to be, and is very nearly, one ten- 
millionth part of the distance measured on a meridian of the 
earth from the equator to the pole, and equals about 39.37 
inches or nearly 3 feet 3! inches. 

The meter is the primary unit of length. 

Upon the meter are based the following primary units: the 
square meter, the are, the cubic meter or stere, the liter, and 
the gram. 

The square meter is the unit of measure for small surfaces; 
as the surface of a floor, table, etc. 

The are is the unit of land measure; this is a square whose 
side is 10 meters in length, and which contains 100 square meters. 

The cubic meter or stere is the unit of volume; this is a 
cube whose edge is i meter in length. 

The liter is the unit of capacity; this is the capacity of a 
cube whose edge is one-tenth of a meter in length. 

The gram is the unit of weight; this is the weight of distilled 
water contained in a cube whose edge is the one-hundredth part 
of a meter; a gram is therefore the one-thousandth part of a 
kilogram, and the one-milHonth part of a metric ton. 

^From The American Chamber of Commerce. 



APPENDIX 



389 



MEASURES OF LENGTH 



Metric Denominations and Values 


Equivalents inDenominations in Use 


Myriameter 


ro,ooo meters 
i,ooo meters 
loo meters 
lo meters 
I meter 
. I meter 
.01 meter 
.001 meter 


6.2137 miles 
.62137 mle, or 3,280 ft. 10 in. 
328 feet I inch 
393.7 inches 
39.37 Inches 
3.937 inches 
.3937 inch 
. 0394 inch 


Kilometer 


Hectometer 


Dekameter 


Meter 


Decimeter 


Centimeter 


Millimeter 





MEASURES OF SURFACE 



Metric Denominations and Values 


Hectare 

Are 


10,000 square meters 

100 square meters 

I square meter 


Centare 



Equivalents in Denominations in Use 

2.471 acres 
119. 6 square j'ards 
1550 square inches 



MEASURES OF CAPACITY 



Metric Denominations and Values 


Equivalent in Denominations in 
Use 


Names 


No. of 
Liters 


Cubic Measure 


Dry Measure 


Liquid or Wine 
Measure 


Kiloliter or stere . . 

Hectoliter 

Dekaliter 

Liter 


1000 

100 

10 

I 

.1 
.01 
.001 


I cubic meter 
. I cubic meter 
10 cu. decimeters 
I cu. decimeter 
. I cu. decimeter 
10 cu. centimeters 
I cu centimeter 


1 . 308 cu. yds. 
2 bush. 3.35 pks. 
9 . 08 quarts 

. 908 quart 
6. 1022 cu. ins. 

. 6102 cu. in. 

.061 cu. in. 


264. 17 gals. 
26.417 gals. 
2.6417 gals. 
1.0567 qts. 

■ 845 gill 

■ 338 fl. oz. 

. 27 fl. dram 


Deciliter 

Centihter 

Milliliter 



390 



APPENDIX 



WEIGHTS 



Metric Denominations and Values 


Equivalents in 

Denominations in 

Use 


Names 


Number of 
Grams 


Weight of What 

Quantity of Water at 

Maximum Density 


Avoirdupois 
Weight 


Metric ton 


1,000,000 
100,000 

I0;000 

1,000 
100 
10 
I 
.1 
.01 
.001 


I cubic meter 

I hectoliter 

I dekaliter 

I liter 

I deciliter 
10 cubic centimeters 

I cubic cent meter 
. I cubic centimeter 
10 cubic millimeters 

I cubic millimeter 


2204.6 pounds 
220.46 pounds 
22.046 pounds 
2.2046 pounds 
3.5274 ounces 
.3527 ounce 
15.432 grains 
1-5432 grains 
.1543 grain 
.0154 grain 


Quintal 


Myriagram 


Kilogram or kilo 

Hectogram 


Dekagram 


Gram 


Decigram 


Centigram 


Milligram 





COMMON MEASURES AND WEIGHTS, WITH THEIR METRIC 
EQUIVALENTS 

The following are some of the Measures in common use, with their equivalents 
in measures of the Metric System 



Common 




Common 




Measures 


Equivalents 


Measures 


Equivalents 


I inch 


2 . 54 centimeters 


I cord 


3 . 624 steres 


I foot 


.3048 meter 


I liquid quart 




9465 liter 


I yard 


.9144 meter 


I gallon 


3 


86 liters 


I rod 


5 . 029 meters 


I dry quart 


I 


loi liters 


I mile 


1 . 6093 kilometers 


I peck 


8 


811 liters 


I square inch 


6.452 sq. centimeters 


I bushel 


35 


24 liters 


I square foot 


. 0929 square meter 


I ounce av'd'p 


28 


35 grams 


I square yard 


.8361 square meter 


I pound av'd'p 




4536 kilogram 


I square rod 


25 . 29 square meters 


I ton (2000 lbs.) 




9072 met. ton 


I acre 


.4047 hectare 


I ton (2240 lbs.) 


I 


016 metric ton 


I square mile 


259 hectares 


I grain troy 




0648 gram 


I cubic inch 


16.39 cu. centimeters 


I ounce troy 


31 


104 grams 


I cubic foot 


.02832 cubic meter 


I pound troy 




3732 kilogram 


I cubic yard 


. 7646 cubic meter 









APPENDIX 



391 



TABLE FOR THE CONVERSION OF METRIC WEIGHTS AND MEASURES 
INTO CUSTOMARY UNITED STATES EQUIVALENTS AND THE 
REVERSE. 

From the legal equivalents are deduced the following tables for converting United 
States weights and measures ; 







METRIC TC 


CUSTOMARY 






Linear 


Measure 




Meters = Inches 


Meters = Feet 


Meters = Yards 


Kilometers = Miles 


1= 39-37 


1= 3.28087 


1 = 1.093623 


1=0.62137 1 


2= 78 


74 


2= 6.56174 


2 = 2 


187246 


2 = 1. 24274 


3 = 118 


II 


3= 9.84261 


3=^3 


280869 


3 = 1.86411 


4 = 157 


48 


4=13.12348 


4 = 4 


374492 


4=2.48548 


5 = 196 


85 


5 = 16.40435 


5 = 5 


468175 


5 = 3.10685 


6 = 236 


22 


6 = 19.68522 


6 = 6 


561738 


6 = 3. 72822 


7 = 275 


59 


7 = 22.96609 


7 = 7 


655361 


7 = 4-34959 


8 = 314 


96 


8 = 26. 24696 


8 = 8 


748984 


8 = 4.97096 


9 = 354 


33 


9 = 29.52783 


9 = 9 


842607 


9 = 5-59233 




CUSTOMARY TO METIUC 

Linear Measure 



Inches = Centimeters 


Feet = Meters 


Yards = Meters 


Miles = Kilometers 


1= 2.54 


1=0.304798 


1=0.914393 


1= 1.60935 


2= 5.08 


2=0.609596 


2 = 1 


828787 


2= 3.21869 


3= 7-62 


3 = 0.914393 


3 = 2 


743179 


3= 4.82804 


4 = 10. 16 


4 = 1. 219191 


4 = 3 


657574 


4= 6.43739 


5 = 12.70 


5 = 1.523989 


5 = 4 


571966 


5= 8.04674 


6 = 15.24 


6 = 1.828787 


6 = 5 


486358 


6= 9.65608 


7 = 17.78 


7 = 2.133584 


7 = 6 


400753 


7 = 11.26543 


8 = 20.32 


8 = 2.438382 


8 = 7 


315148 


8 = 12.87478 


9 = 22.86 


9 = 2.743179 


9 = 8 


229537 


9 = 14.48412 



392 



APPENDIX 



Square Measure 


Cubic Measure 


Square Centi- 


Square Meters 


Square Meters 


Cubic Meters 


Cubic Feet 


Square Inches 


= Square Feet 


= Square Yards 


= Cubic Feet 


= Cubic Meters 


i=o.iS5 


1 = 10. 764 


1= 1. 196 


1= 35-315 


1=0.02832 


2 = 0.310 


2 = 21.528 


2= 2 


392 


2= 70.631 


2=0.05663 


3 = 0-465 


3 = 32.292 


3= 3 


588 


3 = 105.947 


3 = 0.08495 


4 = 0.620 


4 = 43-055 


4= 4 


784 


4 = 141.262 


4=0.11326 


5 = o-775 


5 = 53-819 


5= 5 


980 


5 = 176.584 


5=0.14158 


6 = 0.930 


6 = 64.583 


6= 7 


176 


6 = 210.899 


6=0.16990 


7 = 1.085 


7 = 75-347 


7= 8 


372 


7 = 247.209 


7=0.19821 


8=1. 240 


8 = 86.111 


8= 9 


568 


8 = 282.525 


8 = 0.22653 


9 = 1-395 


9 = 96.874 


9 = 10 


764 


9 = 317.840 


9 = 0.25484 



Square Measure 1 


Liquid Measure 


Square Inches 

= Square 

Centimeters 


Square Feet 
= Square 
Meters 


Square Yards 
= Square 
Meters 


Centimeters 
= Fluid 
Ounces 


Liters = 
Quarts 


Liters = 
Gallons 


1= 6.452 

2 = 12. 903 

3 = 19354 
4=25.806 

5 = 32.257 

6 = 38.709 

7 = 45.160 

8 = 51.612 

9 = 58.063 


1=0.09290 
2=0.18581 
3=0.27871 
4 = 0.37161 
5=0.46452 
6=0.55742 
7=0.65032 
8=0.74323 
9=0.83613 


1 = 0.836 

2 = 1.672 

3 = 2.508 

4 = 3-344 

5 = 4.181 

6 = 5.017 

7 = 5-853 

8 = 6.689 

9 = 7-525 


1=0.338 
2=0.676 

3 = 1.014 

4 = 1.352 

5 = 1.691 

6 = 2.029 

7 = 2.368 

8 = 2. 706 

9 = 3-043 


1 = 1.0567 

2 = 2.1134 

3 = 3.1700 
'4 = 4.2267 

5 = 5.2834 

6 = 6.3401 

7 = 7.3968 

8 = 8.4534 

9 = 9-5101 


1=0.26417 

2 = 0.52834 

3 = 0.79251 
4=1.05668 

5 = 1.32085 

6 = 1.58502 

7 = 1.84919 

8 = 2.11336 

9 = 2-37753 



Dry Measure 


LiQXHD Measure 


Hectoliters = 


Bushels = 


Fluid Ounces = 


Quarts = 


Gallons = 


Bushels 


Hectohters 


Centiliters 


Liters 


Liters 


1= 2.8375 


1=0.35242 


1= 2.957 


1=0.94636 


1= 3-78544 


2= 5-6750 


2=0.70485 


2= 5.915 


2 = 1.89272 


2= 7.57088 


3= 8.5125 


3 = 1.05727 


3= 8.872 


3 = 2.83908 


3 = 11.35632 


4=11.3500 


4 = 1. 40969 


4=11.830 


4 = 3.38544 


4 = 15.14176 


5 = 14.1875 


5 = 1.76211 


5 = 14.787 


5 = 4.33180 


5 = 18.92720 


6 = 17.0250 


6 = 2.11454 


6 = 17.744 


6 = 5.67816 


6 = 22. 71264 


7 = 19.8625 


7 = 2. 46696 


7 = 20. 702 


7 = 6.62452 


7 = 26. 49808 


8 = 22. 7000 


8 = 2.81938 


8 = 23.659 


8 = 7.57088 


8 = 30.28352 


9 = 25.5375 


9 = 3.17181 


9 = 26.616 


9 = 8.51724 


9 = 34. 06896 



APPENDIX 

(Weight Avoirdupois) 



393 



Centigrams = 
Grains 


Kilograms = 
Ounces Avoirdu- 
pois 


Kilograms = 
Pounds Avoirdu- 
pois 


Metric Tons = Long 
Tons 


I = 0.1543 


1= 35-274 


1= 2.20462 


1 = 0.9842 


2=0.3086 


2= 70.548 


2= 4 40924 


2 = 1. 9684 


3 = 0.4630 


3 = 105.822 


3= 6.61386 


3 = 2.9526 


4 = 0.6173 


4=141.096 


4= 8.81849 


4 = 3.9368 


5=0.7716 


5 = 176.370 


5 = 11.02311 


5 = 4.9210 


6=0.9259 


6 = 211 .644 


6 = 13.22773 


6 = 5.9052 


7 = 1.0803 


7 = 246.918 


7 = 15.43235 


7 = 6.8894 


8 = 1.2346 


8 = 282. 192 


8 = 17.63697 


8 = 7.8736 


9 = 1.3889 


9 = 317.466 


9 = 19.84159 


9 = 8.8578 



Grains = Centi- 


Ounces Avoirdu- 


Pounds Avoirdu- 


Long Tons = Metric 


grams 


pois = Grams 


pois = Kilograms 


Tons 


1= 6.4799 


1= 28.3495 


1 = 0.45359 


1 = 1.0161 


2 = 12 


9598 


2= 56.6991 


2=0.90919 


2 = 2.0321 


3 = 19 


4397 


3= 85.0486 


3 = 1.36078 


3 = 3.0482 


4=25 


9196 


4=113.3981 


4=1.81437 


4=4.0642 


5=32 


3995 


5 = 141.7476 


5 = 2.26796 


5 = 5.0803 


6 = 38 


8793 


6 = 170.0972 


6 = 2.72156 


6 = 6. 0963 


7 = 45 


3592 


7 = 198.4467 


7 = 3-17515 


7 = 7.1124 


8 = 51 


8391 


8 = 226.7962 


8 = 3.62874 


8 = 8.1284 


9 = 58 


3190 


9 = 255.1457 


9 = 4.08233 


9 = 9.1445 



INDEX 



PAGE 

Abnormal milk 65 

Acid, butryic, capric, caprylic, myristic, oleic, palmitic, stearic 16 

carbonic, hydrochloric, phosphoric, sulphuric 20 

citric 22 

lactic , 19 

salicylic 127 

sulphuric , g8 

tests 94, 222, 223 

Acidity of milk 94 

of ripened cream in relation to richness of cream 221, 224 

of starters 237 

tests for 222, 223 

Adhesion of milk 37 

Albumen in milk 18 

Albuminoids in milk 16 

Alkali of various strengths for measuring acid in milk and cream 94, 221 

American Association Test for buttermilk and skim-milk 103 

Amphoteric reaction of milk 33 

Antiseptics 59 

Ash in Milk 19 

Babcock test for fat 97 

causes and remedies for common defects in clearness of fat 

in 100 

Bacteria in milk, aroma and flavor producing 215 

as a cause of deterioration of butter 13 

■ classification of 61 

conditions favoring development of 55 

desirable and undesirable in cream ripening 217 

kinds of germs found in milk 60 

number of, in milk 62 

size and shape of . 55 

sources of 62 

unfavorable conditions for. . . 58 

Belt, puUey and speed calculation 385 

Boiler, cleaning of j 384 

priming of 384 

firing 381 

wood or coal for 382 

395 



396 INDEX 

Breeds, composition of milk from various 75 

Brine,, salting butter with 287 

soaking tubs in 300 

Butter,, appearance or style of 342 

classification and grades of, as outlined by N. Y. and Chicago Mercan- 
tile Exchanges 342, 347 

color of 253, 341 

composition of 309 

cost of manufacturing 297 

exportation of 350 

flavor of • 341 

for storage 357, 360 

judging and grading of 340 

keeping in creameries 296 

making of, on farm 180 

mottled, causes and remedy 279 

package, style of 294 

packing of 294 

preparing for market. 294 

printing of 299 

saltiness of 342 

storing in creameries 296 

tests for fat in 107 

texture or body of 341 

treatment of 300 

washing, and kind of wash-water ' 263, 265 

working of 291, 360 

Butter-making, History of i 

Buttermilk, test of loi, 103 

removal of 263 

Butyrin 13 

Calculation of amouit of salt to add to butter 272 

average per cent fat 131 

churn yield 135 

cream-raising coefficient 140 

dividends 137 

overrun 133 

splids in milk 35 

Cans, starter 238 

washing of • 125 

Care of cream on farm 176 

Casein in milk, condition of 17 

Centrifugal separation of cream . . 154 

Churn, keeping in good condition 260 

Churn yield, calculation of i35 

Churned milk, sampling 122 



INDEX 397 



PAGE 

Churning, amount for a 24-7 

color 2^? 

conditions affecting 240 

definition of 239 

degree of ripeness 248 

difficult, causes and remedy for 258 

mixed, sweet, and sour cream 258 

nature of agitation for 249 

richness of cream for 245 

size of globules 252 

straining of cream previous to 253 

temperature 240 

when to stop 255 

Citric acid in milk 22 

Cold storage ^^2 

benefits of ,^3 

cost of 355 

history of 352 

mechanical refrigeration _ 353^ 363, 375 

Cold storage butter, should it be branded 356 

Color, butter 253, 341 

Coloring matter in milk 22, 32 



Commercial starters 



227 



preparation and use of 230 

Composite samples 127 

arrangement and care of 128, 129 

preservatives for 127 

sampling apparatus for 122 

Composition, of butter 309 

acts and rulings as to 309 

analysis thirty years ago 31^ 

of colostrum milk 65 

compounds for increasing yield 310 

control of moisture 312 

of dairy salts 278 

different kinds of milk ^ 

need for regulations 311 

of salty milk 66 

separator slime 166 

tuberculous n ilk 73 

Continuous method of pasteurization 208 

" Cooley" method of cream separation 1^0 

Cooling facilities, for creameries 362 

cooling systems 362 

mechanical refrigeration 353, 363, 375 

natural ice 36 j- 



398 INDEX 

PAGE 

Cows, breeds of 75 

Cream, acidity of, for churning 224 

care of, on farm 176 

effect of cleanliness on quality of 176 

grading of 93 

methods of disposing of 179 

neutralization of 184 

pasteurization of 201 

sour 189 

ripening of 215 

sampling of 118 

Creamery sewage disposal 299, 300 

Curdy specks in butter 285 

Deep-setting system of cream separation 150 

Defe( ts found in butter 323 

advance in lactation 329 

cheesy flavor 324 

• faulty factory conditions 325 

feed flavors 327 

fishy 336 

flat or insipid flavor 323 

flavors by absorption 324 

garlic 327 

metallic flavor 335 

sour flavor 325 

stable flavors 324 

tallowy flavor 332. 

Difficult churning, causes and remedy 258 

Dilution, effect of, on creaming ' • 153 

Disinfectants 59 

Electricity, effect of, on germs in milk 64 

Enzymes in milk 22, 54 

classification 54 

effect of heat on 41 

tests for 42, 201 

Export butter . . . , 350 

Farrington test 223 

Fat, in butter 309 

milk 8 

composition of 15 

condition of 11 

effects of environment 80 

heat on 42 

various feeds on composition of 242 



INDEX 399 

PAGE 

Fat, in milk glycerides of lo 

glycerine in 15 

melting-point of 10, 14 

membrane enveloping fat globules 11 

microscopical appearance of 9 

non-volatile 14 

pajdng for, as compared with fat in cream 143 

properties of 10 

separation of 149 

size of globules 8 

testing for 98, 99, 103, 107 

volatile 13 

Feeds, effects on milk 79 

Fermentations, detection of 67, 94 

various kinds of 67, 71, 73 

Ferments in milk, classification of enzymes 54 

favorable and unfavoral le conditions for 55, 58 

Fibrin 22 

Filtration of water 266 

methods and effects of 266, 269, 270 

Flavors of butter 323 

milk 20, 32, 40 

Food for bacteria 55 

Formula for calculating churn yield 135 

cream-raising coefficient 140 

dividends 137 

overrun 133 

solids in milk 35 

Frozen milk, effects of freezing 123 



Galactase in milk 22 

Garlic, removal of flavor 327 

eradication of 328 

Gases in milk, eliminating 21 

kinds and sources of 20 

Gerber fermentation test .- 95 

Glassware for Babcock test 99 

Grading milk and cream 92 

Gravity separation, different systen s of 35, 49 

Gritty butter 278 



Heat, effects of, on properties of milk 38, 96 

Heating milk previous to skimming 145 

Hydraulic method of separation 153 

Hydrogen peroxide 202 



400 INDEX 

PAGE 

Ice, for cooling cream 374 

refrigeration 365 

Injector 385 

Judging and grading butter 340 

classification 342 

Chicago 347 

New York 342 

export butter 350 

manner of judging 341 

standard for 340 

Keeping property of butter 188, 360 

effect of salt on 273 

Lactation period, effect of, on milk and fat 78 

Lactochrome in milk 22 

Lactometer, comparison of scales on 35 

use of 33. 97 

Lecithin in milk 22 

Lime, its use in creameries 261 

Mammary gland,, description of 23 

inflammation of 30 

Mann's test 222 

Mechanical refrigeration • 353, 363, 375 

Membrane enveloping fat globules 11 

Mercantile Exchange, New York and Chicago grades of butter 342, 347 

Metric system of weights and measures 388 

Milk, abnormal 65 

appportioning skimmed 124 

bitter 69 

bloody 67 

blue and yellow 68 

classification of 3 

colostrum 65 

composition 4 

of, from different animals 5 

definition of 3 

effects of thunder-storms on souring of 64 

fat in skimmed 150 

fever 30 

from barren and spayed cows 72 

from cows a long time in milk 71 

grading of 92 

necessity of good 117 

properties of, physical and chemical 32 



INDEX 401 

PAGE 

Milk, ropy 68 

salty 66 

sampling of 1 18 

frozen, churned, and sour 122, 123 

secretion of, conditions affecting 28 

theories 26 

from sick cows 72 

specific gravity of 2;^ 

specific heat of 38 

variation in quality of, and causes 74 

water of 6 

Milk and its products as foods 43 

biological classification 45 

ash 46 

proteins 46 

unidentified substance 

in milk fat 47 

chemical classification 44 

Milking, frequency of 75 

manner of 76 

Moisture control • 312 

factors that aid in 318 

tejts of butter 293 

Mold, in butter 304 

on butter 306 

conditions fa^•orable to growth 307 

discolorations 307 

propagation 307 

sources of 307 

Mottles,, causes of, in butter 279 

kinds of 281 

prevention of .' 284 

Natural starters, preparation of , 226 

Neutralization, "neutralization" of cream 183 

neutralization of cream for butter-making 184 

neutralization, principle of 183 

other neutraUzers 199 

pints of lime mixture required to reduce acidity to .25 per 

cent (Table) 196 

the preparation and use of lime as a neutralizer 192 

Non-volatile fats 14 

Nuclein in milk 22 

Oil separator 385 

Olein, effect of variation of, on softness of butter 14 

Opacity of milk ; 32 



402 ■ INDEX 

PAGE 

Overrun, definition and calculation of 133 

factors governing 133 

what should it be 135 

Packing butter , 294, 360 

kind and style of package 294 

for storage 360 

treatment of tubs pre\ ious to 300 

Palmitin 14, 1 5 

Paraffining of tubs 302 

Parchment paper, treatment of. . 304 

Pasteurization, advantages of 201, 214 

cost of 212 

definition 201 

disadvantages of 214 

good milk and cream important 204 

methods of 208 

sanitation 206 

Storch Test for 201 

temperatures 203 

Pasteurizers, durability and efficiency 210 

Pajdng for fat in cream as compared with fat in milk 143 

Proteids in milk, as a cause of m.ottles in butter 280 

kinds of 16 

Quevenne lactometer • 34 

Receiving milk and cream 92 

Richness of cream from centrifugal separator 81 

gravity separation 151 

Ripening cream, definition 215 

degree of acidity to ripen to 224, 248 

kinds of acids produced from 215, 217, 229 

mixing starter with cream 221 

objects of 215 

temperature 220 

tests for acidity 221 

Salt, as a cause of mottles 279 

composition of American and Danish 278 

condition of, when added to butter 277 

effect of, on keeping property of butter 273 

removal of buttermilk 275 

in relation to water in butter 275 

kind and condition of 277 

undissolved, in butter 278 

Salt test, chemical changes 288 

features of ,.,.,.,.,.,,,, 289 



INDEX 403, 



PAGE 

Salt test, principle of 2S8 

to make 290 

Salting butter, amounts of salt to use 272 

effects of, on keeping property' of butter 273 

purpose of 272 

with brine 287 

Samples, average 130 

composite 127 

Sampling- tube 1 20 

Score-card for butter 340 

Sediment test 116 

Separation, advantages of centrifugal 155 

centrifugal 154 

classification of centrifugal machines 158 

conditions affecting completeness of 161 

effect of speed as compared with dian-.-eter on 164 

factors governing richness of cream 81 

gravity 35, i49 

heating milk for 145 

history and development of 155 

process of centrifugal 158 

Separators, farm, introduction and development 168 

objections to 171 

power for 174 

reasons for introducing 168 

thickness of cream 172 

Separator slime, composition of 165 

Sewage-disposal plants, cuts of 209, 300 

Shallow-pan creaming 149 

Skimmed milk, apportioning 124 

Standards, legal, for butter 317 

dairy products 387 

Starter cans 238 

Starters, amount to use 221, 237 

commercial 227 

definition, history, and classification 225, 226 

inoculation 232 

length of time to carry 236 

milk powders for 235 

natural 226 

poor 236 

preparation of 226, 230 

Statements,, annual 141 

patrons' monthly 141 

Sterilization 203 

Storch test 201 

Streaked butter 281 

Sugar in milk 18 



404 INDEX 

PAGE 

Table showing effect of temperature on growth of bacteria 56, 57 

fat and total solids of milk from various breeds 76 

Taints in milk, eliminating 21, 40 

sources of 20 

Temperature, churning 2.1.0 

duration of 245 

effect of, on bacterial growth 5^,57 

for storing butter 296 

pasteurization : 202 

ripening ■ , 220 

separation 145 

wash-water 263 

Tests, acid 94, 221 

fat ■ ; 97 

in butter '. 107 

buttermilk and skim-n.ilk loi 

cream 99 

milk 98 

Tests, fermentation 94 

pasteurized milk 201 

Total solids in milk, variation of \ 5 

Tubs and boxes, paraffining of 302 

styles of 204 

treatment of 300 

Udder, external appearance of 30 

internal structure of 23 

Urea in milk 22 

Utensils, cleaning 1 25, 166 

Variation of fat in cream, causes of 81 

amount of water or skim milk used to flush the bowl 90 

cream screw arijustn.er.t 82 

rate of inflow 85 

richness of milk 83 

speed of m.achine 8j 

temperature of milk 8S 

Variation of fat in milk, causes of 74 

advance in lactation 78 

age of cow 78 

breed of cows 75 

condition of cow 80 

environment 80 

feed of cows 79 

fore and after milk 77 

individuality of cows ' . . 74 

manner of milking 76 

time between milkings 75 



INDEX 405 

PAGE 

Viscogen, use of 39 

Viscosity of milk 37; 39 

restoration of ; 39 

Vitamines 47 

Volatile fats , , 13 

Washing butter, kind of wash-water for 265 

purpose of 263 

Washing cans 125 

Water in butter, condition of 257 

control of 312 

Water, filtration 266 

in relation to salt in butter 275 

methods of purifying , . 266 

pasteurization 266 

Wisconsin curd test 95 

Working of butter, for storage 360 

objects and effects of 291 



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